Mechanical Questions & Answers.docx

Maintenance, Repair And Operations (MRO) Interview Questions  Question 1. What Are The Duties Of A Maintenance And Repair Worker? Answer : The maintenance and repair worker duties includes:       

Building partitions Make a plaster or drywall repairs Fix or paint roofs Fix worn or broken parts Maintain and repair specialized equipment’s Inspect mechanical parts like motors, belts, drives, fluid levels and perform other maintenance actions Drywall repairs

 Question 2. What Is The Skill Required To Become Maintenance And Repair Worker? Answer : To become maintenance and repair worker you must know:       

Basic calculation Safety practices and handling tools Basic plumbing repair skills Basic knowledge of electrical wiring Ability to decipher written or oral instructions Physical agility Able to lift and move heavy objects.

 Question 3. Mention What Are The Challenges That Maintenance And Repair Work Usually Face? Answer :     

Unusual working condition like bad weather or low temperature May have to work in an unusual shift May have to work in a messy area May sometimes be physically distressing and exhausting May have to work in dangerous places like working at height or working with electrical appliances and wires.

 Question 4. What Is The Potential Risk That Repair And Maintenance Work Usually Face?

Answer : The potential risk that repair and maintenance worker faces are: Faulty electrical: Risk of electrocuted always remains with repair and maintenance workers, if not equipped with electric-proof tools and attires. They are prone to burns, shocks, etc. Lifting equipment: Workers usually have to deal with heavy metal objects and lifting equipment is not inspected or maintained then they are at risk of a fatal accident Maintenance of working and walking surfaces: Slippery working surfaces, sharp tools and nails scattered on working surface, slip and trip, uneven and potholed are some potential hazard that may cause an accident Dust: It potential risk for the workers specially working in woodworking or iron industries.  Question 5. Mention What Are The Precaution Measures Taken By The Repair And Maintenance Worker At Working Site? Answer : The precaution measures taken at the working site is:   

Overhead and side clearances are adequate to permit the safe operation of the lift truck Aisles, floors and passageways should be kept clear and free of hazards To avoid the accumulation of vapours from the refueling and operation of its lift trucks, workplace should be adequately ventilated.

 Question 6. What Care Has To Be Taken Care When Doing Gas Welding? Answer : While doing gas welding worker should:       

Should wear proper protective before doing gas welding Valve protection caps should be in a secured place When cutting is done, they should be secured on a pallet or springboard Cylinder should be transported in a vertical situation For lifting cylinders, valve protection caps shall not be used for lifting from one vertical position to another Oxygen and fittings shall be kept away from oil or grease Any faulty or defective equipment should be reported to the supervisor.

 Question 7. How Can One Become A General Maintenance Worker? Answer :

To become general maintenance worker the individual should learn some basic skills in high school or technical classes, community college or postsecondary trade of vocational schools. Student aspire to become maintenance worker can also observe and learn maintenance skill.  Question 8. While Doing Welding What Are The Safety Measures That Worker Should Follow? Answer : While doing welding, workers should follow the rules like: Respirator or welders mask: Use mask or respirators as per your projects, match the filter to the types of metals and coatings used Ventilation: Welding area should have proper ventilation; improper ventilation can cause “plume poisoning.” Clean and tidy area: Make sure the area you working is clean and check for any leaks Storage: Flammable substance should be kept in a proper storage locker Eye protection: Eye protection can protect against injuries due to debris and the effects of the ultraviolet light Fire protection: The sparks from welding can set fire, proper fire extinguisher should be kept in reach of the welding area Protective clothing: Body parts like hands and legs should be a cover with protective and clothes which can bear heat and spark emitted from the welding.  Question 9. What Are The Factors That Can Lead To The Psychological Risks And Stress? Answer : Psychological risk arises from:       

Excessive workloads Psychological harassment by third party Conflicting demand and lack of communication Lack of role clarity Lacking decision-making skill Poorly managed organization Working in overtime

 Question 10. What Does The Carpentry Maintenance Worker Do? Answer : Carpentry maintenance worker does many things like:

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Assist in measuring, marking and arranging materials according to blue-print Cuts and shapes materials such as wood, fiberglass and drywall manually as well as with power tools Assists with the repairing and constructing miscellaneous items of the wooden structure Assisting with replacing of floors, wall sidings, doors, etc. Installation of partitions, doors and walls Assisting with the erection of scaffolding Inspect wooden structure and build forms for pouring concrete

 Question 11. Mention What Are The Duties Of A Construction Maintenance Worker? Answer :         

Inspect the structures and identify the cause of the problem Fix the broken parts and giving final finishing touch to repair and construct repairs Sound knowledge of using hand and power tools like wrenches, hammers and screwdrivers Repair and maintain system that control the temperature Monitor the work orders and repair jobs accordingly Read catalogs, blueprints and manuals Check prices with suppliers Estimate costs of a job Do almost all types of maintenance work

 Question 12. Mention What Are The Tools Used By Road Maintenance Worker? Answer : Tools used by road maintenance worker are:        

Swiss hammer Drills Jackhammers Road-rollers Epoxy guns Chain drags Pressure washers Sand blasters, Saws, etc.

Maintenance And Manufacturing Interview Questions  Question 1. What Is Maintenance And Manufacturing? Answer : Maintenance is one of the major activities in manufacturing as it highly influences production quality and quantity and directly affects production cost and customer satisfaction. As new

manufacturing technologies emerge and global communication advances, new maintenance practices are developed to cope with these changes.  Question 2. What Is The Role Of Maintenance In Maintaining? Answer : The role of maintenance in maintaining asset value over time is getting more visible at the business level with the increase in its acquisition and maintenance costs. various manufacturing systems are introduced along with their distinctive features that influence maintenance strategies and practices.  Question 3. What Are The Types Of Manufacturing Systems? Answer : The oldest type of manufacturing system is the custom manufacturing where a person or a machine makes a certain product tailored to a specific need. A shoemaker is an example of this system. Modern manufacturing have intermittent, continuous or flexible production systems.  Question 4. What Is Fms? Answer : The most flexible and responsive to changes manufacturing system is the flexible manufacturing system (FMS). It absorbs sudden large scale changes in production volume, capacity and capability. FMS produces a product just like intermittent manufacturing and is continuous like continuous manufacturing.  Question 5. What Are The Main Advantage Of Fms? Answer : The main advantage of FMS is its high flexibility in managing manufacturing resources. The resulting gains are numerous including:      

Reduced manufacturing cost, Greater labor productivity, Greater machine efficiency, Improved quality, Increased system reliability, Shorter lead times.

However, FMS implementation requires a large initial capital and substantial preplanning. It also requires high skilled labor.  Question 6. What Is Maintenance In Manufacturing?

Answer : Maintenance in the manufacturing environment is one of the most complicated types of maintenance in comparison to construction, transportation and service business. Manufacturing is becoming highly competitive with extremely high pressure in reducing cost and increasing value of assets and improving the quality of outcomes (products). Manufacturing systems has grown over the years to be parts of global networks and supply chains. All of these changes in the manufacturing business have put maintenance in a great pressure on developing more effective and efficient operations. Other special feature of manufacturing environment that makes it distinct from other environment is its complicated interrelation with large number of stakeholders, internal and external. The management structure in manufacturing environment is usually highly structured with many several decision layers and many parallel functional areas.  Question 7. What Is Maintenance Management? Answer : The main decisive factor for maximizing manufacturing asset value in terms productivity, reliability, cost, etc. is maintenance management, the body of the organization that is in charge of planning, implementing, controlling, and improving maintenance activities. Maintenance management is often considered as a centralized functional unit within the overall organizational structure in parallel with other functional units such as, production, Decentralized maintenance units is another common structure adopted by large organizations with multiple production units. The decision of adopting centralized or decentralized management structure is usually mad at the high management level taking into consideration, the size of the organization, the complexity of its operations, and the organization culture.  Question 8. What Are The Elements Included In Technical And Operational Plans? Answer : 1. 2. 3. 4.

Maintenance philosophy Maintenance load forecasting Maintenance capacity Maintenance scheduling.

 Question 9. What Is Maintenance Philosophy? Answer : Maintenance philosophy is the step of designing on the general maintenance concept selected from known best practices as the maintenance philosophy for the organization. Total productive maintenance and reliability based maintenance concepts are two widely spread concepts. The selected concept is supported with right combinations of maintenance strategies such as preventive maintenance, condition based maintenance, and shutdown maintenance.  Question 10. What Is Maintenance Load Forecasting?

Answer : Maintenance forecasting is a major part of planning concerned with estimating the current and future amount of maintenance work and type needed. Maintenance load forecasting is a complex task that involves a lot of uncertainties and influenced by many factors such as the age of the equipment, the rate of use, usage climate, and skills of workers.  Question 11. What Is Maintenance Capacity? Answer : Capacity planning is the translation of the maintenance load into resource needed to meet the forecasted load. Resources include, number and skills of craftsmen, maintenance tools, labor, material, spare parts, etc.  Question 12. What Is Maintenance Scheduling? Answer : Maintenance scheduling is the process of assigning resources for tasks to be accomplished at a certain time in a certain frequency. Scheduling of tasks should take into account production schedules, optimization of resources and reducing costs.  Question 13. What Are The Responsibility Of Maintenance Management Includes? Answer : The organizing responsibility of maintenance management includes: 1. Job design 2. Time standards 3. Project management. Job design involves defining for each major maintenance job, the work content, the method of maintenance the required skills and the needed tools. Time standards are determined for major components of major maintenance jobs following the scientific approach. This helps in controlling maintenance tasks and efficient utilization of resources. It is also useful for planning and scheduling maintenance activities and forecasting workload. Project management is used for optimizing and controlling major complex time consuming maintenance operations, such as shutdown maintenance projects for large plants. Critical Path Method (CPM) and Program Evaluation and Review (PERT) are common project management tools.  Question 14. What Are The Controlling Activities Of Maintenance Management Include? Answer :

Controlling activities of maintenance management include the following: 1. 2. 3. 4.

Work Control Inventory Control Cost Control Quality Control.

Work control is done using work order system in an integrated data base system for controlling reporting and analyzing. Intelligent maintenance systems are developed and integrated with ERP systems are commonly used and proven to be efficient and effective. Inventory control is an important element of maintenance management that ensures the availability of spare parts and tools in the right quantity at the right time. Ordering and reordering quantities taking into consideration costs and lead times are built into automated information systems to assist management in this task by raising red flags at reorder points. Cost control involves tracing all cost components of maintenance activities that include direct maintenance costs, lost production, equipment degradation, backups, and over maintenance costs. Quality control of maintenance work involves assuring that the maintenance work is following standards and producing the expected results. Control is done by the supervision and testing final outcomes following a predetermined control procedure.  Question 15. What Are The Maintenance Concepts And Strategies? Answer : Several maintenance concepts were developed in different parts of the world that are usually based on cultural and philosophical backgrounds. These trends encompass other strategies and technologies of maintenance. Some of these concepts are briefly introduced below: 1. Total Productive Maintenance 2. Reliability Centered Maintenance 3. Maintenance Strategies  Question 16. What Is Total Productive Maintenance? Answer : Total Productive Maintenance (TPM) is developed from the preventive maintenance methodology introduced from the USA and further developed and implemented in many Japanese companies since 1971. It is then spread throughout the world. TPM is defined as a system of maintaining and improving the integrity of production and quality systems through the machines, equipment, processes and employees that add business value to the organization. Total Productive Maintenance (TPM) is a proactive and costeffective approach to maximize equipment effectiveness using the principles of teamwork, empowerment, ‘zero breakdowns’ and ‘zero defects’.

 Question 17. What Are The Key Objectives Of Total Productive Maintenance (tpm)? Answer : Some of the key objectives of TPM are:       

Focus and improve people management to minimize the targeted losses. Develop the policy, strategy and early management activities to ensure easy maintenance of the equipment. Develop the autonomous maintenance system to empower the production operators to take care of the conditions and effectiveness of the equipment. Develop a planned maintenance of the machine and equipment. Provide training and education to the operators and maintenance personnel to upgrade their equipment-related knowledge and skills. Establish safety practices and also prevent adverse environmental effects. Reduce the wastage of organizational resources.

 Question 18. What Are The Elements Of Tpm? Answer : There are seven major elements of TPM as follows [5]: 1. 2. 3. 4. 5. 6. 7.

housekeeping on the production line, cross-training of operators to perform maintenance tasks, teams of production and maintenance personnel, operator involvement in the maintenance delivery system, disciplined planning of maintenance tasks, information tracking of equipment and process condition and plans, Schedule compliance to the maintenance plan.

 Question 19. What Is Reliability Centered Maintenance? Answer : Reliability Centered Maintenance (RCM) was initiated by the commercial aviation industry and then adopted by the U.S. military in the 1970s and then by the U.S. commercial nuclear power industry (in the 1980s) followed by other commercial industries and fields in the early 1990s. RCM is defined by the technical standard SAE JA1011, as ‘‘an engineering framework that enables the definition of a complete maintenance regime. It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context’’.  Question 20. What Are The Primary Principles Upon Which Rcm Is Based? Answer : The primary principles upon which RCM is based are the following:

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     

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Function oriented. It seeks to preserve system or equipment function. Device group focused. It is concerned with maintaining the overall functionality of a group of devices rather than an individual device. Reliability centred. It uses failure statistics in an actuarial manner to look at the relationship between operating age and the failures. RCM is not overly concerned with simple failure rate; it seeks to know the probability of failure at specific ages. Acknowledges design limitations. Its objective is to maintain the inherent reliability of the equipment design, recognizing that changes in reliability are the province of design rather than maintenance. Maintenance can only achieve and maintain the level provided for by design. Driven by safety and economics. Safety must be ensured at any cost; thereafter, costeffectiveness becomes the criterion. Defines failure as any unsatisfactory condition. Therefore, failure may be either a loss of function (operation ceases) or a loss of acceptable quality (operation continues). Uses a logic tree to screen maintenance tasks. This provides a consistent approach to the maintenance of all kinds of equipment. Tasks must be applicable. The tasks must address the failure mode and consider the failure mode characteristics. Tasks must be effective. The tasks must reduce the probability of failure and be cost effective. Acknowledges two types of Maintenance tasks and Run-to-failure. The tasks are Interval (Time- or Cycle-)-Based and Condition-Based. In RCM, Run-to-Failure is a conscious decision and is acceptable for some equipment. A living system. It gathers data from the results achieved and feeds this data back to improve future maintenance. This feedback is an important part of the Proactive Maintenance element of the RCM program.

 Question 1. How Cavitation Can Be Eliminated In A Pump? Answer : Cavitation means bubbles are forming in the liquid.   

To avoid Cavitation, we have to increase the Pump size to One or Two Inch; To increase the pressure of the Suction Head, or Decrease the Pump Speed.

 Question 2. Which Pump Is More Efficient Centrifugal Pump Or Reciprocating Pump? Answer :

Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.  Question 3. Why Centrifugal Pump Is Not Called As A Positive Displacement Type Of Pump? Answer : The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure. Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change. One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.  Question 4. Why The Centrifugal Pump Is Called High Discharge Pump? Answer : Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following formulae: Centrifugal force F= (M*V2)/R. Where, M-Mass V-Velocity R-Radius  Question 5. Why Cavitation Will Occur In Centrifugal Pumps And Not In Displacement Pumps? Answer : The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than the flow area of pipe. This decrease in flow area of pump results in increase in flow rate. So pressure drop happened between pump suction and the vanes of the impeller. Here air bubbles or cavities are formed because of liquid vapour due to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.  Question 6. What Is A Radialflow Turbine?

Answer : In a radialflow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.  Question 7. What Are Four Types Of Turbine Seals? Answer : 1. Carbon rings fitted in segments around the shaft and held together by garter or retainer springs. 2. Labyrinth mated with shaft serration’s or shaft seal strips. 3. Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting. 4. Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.  Question 8. What Are Two Types Of Clearance In A Turbine? Answer : 1. Radial – clearance at the tips of the rotor and casing. 2. Axial – the foreandaft clearance, at the sides of the rotor and the casing.  Question 9. What Is The Function Of A Thrust Bearing? Answer : Thrust bearings keep the rotor in its correct axial position.  Question 10. What Is A Stage In A Steam Turbine? Answer : In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.  Question 11. What Is A Diaphragm? Answer : Partitions between pressure stages in a turbine’s casing are called diaphragms. They hold the vaneshaped nozzles and seals between the stages. Usually labyrinthtype seals are used. Onehalf of the diaphragm is fitted into the top of the casing, the other half into the bottom.  Question 12. What Are The Two Basic Types Of Steam Turbines?

Answer : 1. Impulse type. 2. Reaction type.  Question 13. What Are Topping And Superposed Turbines? Answer : Topping and superposed turbines arc highpressure, noncondensing units that can be added to an older, moderatepressure plant. Topping turbines receive highpressure steam from new highpressure boilers. The exhaust steam of the new turbine has the same pressure as the old boilers and is used to supply the old turbines.  Question 14. What Is A Combination Thrust And Radial Bearing? Answer : This unit has the ends of the Babbitt bearing extended radically over the end of the shell. Collars on the rotor face these thrust pads, and the journal is supported in the bearing between the thrust collars.  Question 15. What Is Cavitation? Answer : Cavitation is the formation of vapor cavities (Air bubbles) in a liquid.  Question 16. What Is Positive Displacement Pump? Answer : Positive displacement pumps are those that operate by forcing a fixed volume of fluid from the inlet pressure section of the pump into the discharge zone of the pump.  Question 17. What Is Kinematic Viscosity? Answer : The kinematic viscosity is the ratio of absolute viscosity to the density of the liquid.  Question 18. Differentiate Between The Uniform Flow And Non-uniform Flow? Answer : Uniform Flow: The flow is defined as uniform flow when in the flow field the velocity and other hydrodynamic parameters do not change from point to point at any instant of time.

Non-Uniform Flow: When the velocity and other hydrodynamic parameters changes from one point to another the flow is de􀃡ned as non-uniform flow.  Question 19. What Is The Difference Between The Unsteady Uniform Flow And Steady Uniform Flow? Answer : Unsteady uniform flow - changes with time. Steady uniform flow - does not change with time.  Question 20. What Is Coefficient Of Contraction? Answer : Coefficient of contraction is the ratio of area of jet at vena contracta to the area of orifice. The typical value may be taken as 0.64 for a sharp orifice (concentric with the flow channel). The smaller the value, the more effect the vena contracta has.

 Question 1. What Is Cfm? Answer : The notation CFM (Cubic Feet per Minute) refers to a volume of air produced by the air compressor at a given pressure or PSI (Pound per Square Inch)  Question 2. What Is Duty Cycle? Answer : A compressor’s duty cycle determines the percentage of run time in a full cycle. A full cycle is determined by adding the compressor run time to its rest time.

 Question 3. Does A Compressor That Has 100% Duty Cycle Mean That I Can Run The Compressor All The Time? Can I Run My Compressor 24 Hours A Day? Answer : No, you’ve got to remember that duty cycle is rated at 100PSI, at an ambient temperature of 72°F, but certainly a 100% duty cycle compressor can run for much longer periods of time than a 30% duty compressor under the same conditions.  Question 4. Which Is Best Compressor For On-board Setup? Answer : Either the 400C 12V air compressoror the 450C 12V air compressor for setup.  Question 5. How Do I Know If I Want The 400c Or 450c? Answer : The 400C pump is rated at 150psi working pressure and the duty cycle on this unit is rated at 33% duty at 100psi in 72 degree ambient temp. The 450C is rated at 150psi working pressure, the duty is rated at 100% at 100psi at 72 degrees ambient temp. TIP: If you need duty cycle, go with the 450C. If you want speed, go with the 400C (it is faster than the 450C).  Question 6. What Else Would Best For My On-board System? Answer : component parts for an onboard air system: PART NUMBER TA-508: 5.0 Gallon Tank with 8 Ports PS-150R: 110/150 PSI Pressure Switch VA00035: 35ft Hose with Close-ended Tire Chuck  Question 7. Does A New Compressor Have To Be Broken In? Answer : No, they do not. Typically after an install, you should power up the system from 0 to whatever the cut-off pressure is and check for any leaks that may be present.  Question 8. How Do You Check For Leaks? Answer : You can check for leaks by putting soap and water solution where the fitting connections are. If there are bubbles present that grow in size, then there are leaks.

 Question 9. Does It Matter Where I Install My Compressors On My Vehicle? Answer : This depends on several factors such as available space, whether or not the compressor is of a sealed or vented type, as well as personal preference and aesthetics. Make sure to utilize the rubber insulators to keep vibration and noise to a minimum.  Question 10. How Can I Tell Whether The Compressor Is Sealed Or Non-sealed? Answer : Manufacturers will normally specify if a compressor is sealed against moisture and dust, and in many cases, you can tell the difference by simply inspecting the compressor. If you see vents, cracks, or holes in the motor housing, then the compressor is not sealed and must be kept away from dust and moisture.  Question 11. Why Is It Important To Have A Sealed And Moisture-resistant Compressor? Answer : The preference of a sealed-type compressor is due to the fact that in mobile pneumatics, compressors are likely to be exposed to outside elements.  Question 12. Is The 550c Compressor Sealed And Weatherproof? Answer : The 550C is not a sealed unit. If you want to mount a compressor under your truck, you might want to take a look at our 450 series. While it is not as fast as the 550 series, it is moisture and dust resistant and can be mounted under your truck. Also, we have new compressors that are more suited to exterior mounting (420, 460C, and 480C).  Question 13. Is It Possible To Mount The Compressor Sideways? Must It Be Mounted With The Cylinder Upright? Answer : Yes, you can mount our compressors in any direction or position because they are oil-less. The only position we do not recommend is an upside-down mount, since heat tends to travel upward.  Question 14. If I Mount My Compressor Sideways, Like On The Frame Rail Of My Truck, Is There Anything I Should Be Careful Of When Doing This? Answer :

you mount your compressor sideways to the frame rail, you should periodically check to make sure that your compressor is mounted securely. Use a thread-locking compound to keep the screws from backing off and causing the compressor to be mounted loosely.  Question 15. Is It Possible To Hook Up More Than One Compressor To A Single Pressure Switch? Answer : Yes, it is possible to use one pressure switch on more than one compressor. You should always run a relay if you want to hook up multiple compressors to a single switch. You should check the amp draw on the switch first, and then you’ll know how many compressors you can hook up to one switch.  Question 16. Is It Possible To Use An Adjustable Pressure Switch With My Compressor? Answer : May not use adjustable pressure switches with any VIAIR compressor. If you use an adjustable pressure switch, you can set the pressure switch higher than the maximum pressure that is rated for your compressor, or you may exceed the maximum rated working pressure for your air supply tank. Doing so will immediately void your warranty, not to mention, it is dangerous.  Question 17. Is Amp Draw Of The Compressor Something I Need To Be Concerned With? Answer : Yes, the lower the amp draw, the better the compressor is. As a rule of thumb, the maximum amperage that a compressor should require is 30amps.  Question 18. How Often Should We Change The Oil? Answer : In a rotary screw compressor, oil should be changed about every 7000-8000 hours. This depends on the type of compressor you purchase. For a Reciprocating air compressor, generally you would change the oil approximately every 3 months. For a more accurate time frame, call in with a model number to find the recommended schedule for your compressor.  Question 19. When Should I Replace The Air Intake Filter? Answer : If your compressor has an Air Intake Filter, it should be cleaned on a weekly basis (assuming you are using the compressor about 3 days a week). When the filter starts to develop debris that is becoming harder to clean out, or you notice any tears or holes in the filter, the filter should be replaced.

 Question 20. What Is The Difference Between Stop-start And Constant Run? Answer : Simply put, a start-stop air compressor has a pressure switch that turns the machine on and off. Most small electric and small gas air compressors are start-stop. A constant run compressor means the motor continuously runs and continuously turns the pump. Many industrial shops who need consistent air on a daily basis will purchase a constant run compressor.  Question 21. What Voltage Do I Run On? Answer : It depends on the size of Compressor. Most Homeowner sized small compressors are built to run on a single 110V Outlet. As you get into larger models, many compressors offer the choice between 110 to 460 voltage.  Question 22. Will My Compressor Run On A Generator? Answer : The compressor should be able to run given the proper requirements, however we recommend not using a compressor with a generator. Generators have fluctuations in power, and because a compressor needs constant voltage to be able to run, it is generally best not to use a generator if no power is available.  Question 23. What Happens When Water Stays In My Compressor? Answer : Compressor tanks are made of steel, which means if water is left in the tank, rust will start to accrue. Depending on the severity, contact your local service center about the best way to eliminate the problem. One place to start would be to look into purchasing an air dryer, to help eliminate the problem.  Question 24. What Happens If There Is Water In My Lines? Answer : Generally this is caused by two problems - either a failed condensate trap or a failed or undersized air compressor dryer. To solve the first problem, you will need to either clean the water trap or simply replace it. The second problem is a bit trickier, as you would need to repair or replace your air dryer with something larger (unfortunately, this can be a bit pricy).  Question 25. What Size Of Hose Should Be Used? Answer :

This will depend on the type of compressor that you have. The two most common sizes are 1/4" and 3/8". Check your compressor manual, or give us a call to help find the right size to use. Generally, the larger the compressor means the larger size of diameter you can use. Most homeowner compressor manufacturers would recommend a 1/4" hose diameter.  Question 26. What Is The Maximum Hose Length I Should Use With My Compressor? Answer : This will also depend on the size of compressor and CFM required. The Maximum hose length is one of the most open ended questions related to air compressors. For a small homeowner unit, it would be smart not to exceed 150'. For a shop or industrial compressor, contact your local installation provider or give us a call to help figure out your maximum length.  Question 27. How Much Air Will I Need To Power My Air Compressor Tool? Answer : Generally, most air tools will take around 70-100 PSI, and will consume less than 10 CFM, however consult the manual or manufacturer of your tool for exact air requirements.  Question 28. How Often Until A New Compressor Is 'broken In'? Answer : Air Compressors do not need to be broken in. Check for any leaks or malfunctions during the first start-up, but after that you should be ready to go.  Question 29. What Is A Good Tank Size? Answer : The tank size you will use will depend on the amount of air that you need stored. A benefit to a larger tanked air compressors is that the motor will not start and stop as often as a smaller tanked compressor. However, if you do not believe that you will use a good amount of air, it may be smarter and cheaper to use a smaller tank.  Question 30. What Is The Difference Between A Rotary Screw Compressor And A Reciprocating Compressors? Answer : A rotary screw compressor is one that utilizes two intermeshing helical rotors to trap a volume of air, then compress it to a higher pressure. Rotary screw compressors can be run at lower temperatures for 24 hours per day, 365 days a year.

A piston compressor (aka reciprocating) uses pistons driven by a crankshaft to deliver air at high pressure.  Question 31. Will My Small Homeowner Air Compressor Be Able To Handle An Extra Tank? Answer : It depends on whether or not you have a continuous duty air compressor or not. A continuous duty compressor means that it is able to run for long periods of time (aka continuously). This type of compressor will not have any problems running a larger spare tank. If it is not continuous duty then it might have a tougher time. Depending on the size of your machine and the receiver tank, it should be able to handle it. Just be sure that you give it time to cool off when filling the tank, otherwise you would be going overboard.  Question 32. Why Does My Compressor Leak Air When The Compressor Shuts Off? Answer : Most air compressors have a one way check valve between the compressor pump and the air receiver. When the compressor shuts off the check valve prevents the high pressure air from traveling back from the receiver to the pump. This allows for an unloader valve to release the pressure on the pump to atmosphere to allow for easier startup. The unloader system can be of several different designs. Two of the more common types are pressure switch mounted or centrifugal mounted on the end of the crankshaft.  Question 33. Why Does The Safety Valve On My Compressor Pump Make A "popping" Sound? Answer : This is most commonly an indication of bad valves. Depending on the model valves could be rebuilt or replaced.  Question 34. Why Does The Safety Valve On My Tank Blow Off? Answer : This is caused by a pressure switch improperly installed, set too high or malfunctioning. Safety valves do not normally fail on their own.  Question 35. Why Doesn't My Air Compressor Produce As Much Air As It Used To? Answer : The most common cause is bad valves. It is also important to check your entire system for higher air consumption or leaks.

 Question 36. Why Compressor Shuts Down On High-temperature? Answer : If your compressor trips on over temeprature, it could be any of the following:      

Ambient temperature too high or not enough ventilation. Too low oil level. Wrong type of oil. Dirty oil cooler. Thermostatic valve not working. Dirt / obstruction in oil lines.

 Question 1. What Is Local Comfort Cooling System? Answer : They may be integrated, with heating, ventilation and air conditioning provided by a single system, for example, air handling units connected to ductwork, or they may be a combination of separate systems, for example mechanical ventilation but with radiators for heating and local comfort cooling units.  Question 2. What Is Centralised Air System? Answer :

The most common central cooling system is a split system, which includes an outdoor cabinet containing a condenser coil and compressor, and an indoor evaporator coil, usually installed in conjunction with your furnace. or air handler . The compressor pumps a chemical called refrigerant through the system.  Question 3. What Is Constant Volume System? Answer : Constant Air Volume (CAV) is a type of heating, ventilating, and air-conditioning (HVAC) system. In a simple CAV system, the supply air flow rate is constant, but the supply air temperature is varied to meet the thermal loads of a space. Most CAV systems are small, and serve a single thermal zone.  Question 4. What Is Variable Air Volume System & Dual Duct System? Answer : Variable Air Volume (VAV) is a type of heating, ventilating, and/or air-conditioning (HVAC) system. Unlike constant air volume (CAV) systems, which supply a constant airflow at a variable temperature, VAV systems vary the airflow at a constant temperature.  Question 5. What Is Hydronic System Or Air-water System? Answer : Hydronic systems circulate hot water through warming baseboards, radiators and/or radiant tubing in your floors or ceilings. There are many advantages to heating your home using a hydronic system, whether it is for a new home or as a replacement heating system.  Question 6. How Vapour Compression Cycle Works ? Answer : The Vapor-Compression Refrigeration Cycle is comprised of four steps. ... The condenser is in contact with the hot reservoir of the refrigeration system. (The gas releases heat into the hot reservoir because of the external work added to the gas.) The refrigerant leaves as a high pressure liquid.  Question 7. What Is Vapor Compression Cycle? Answer : Vapor-Compression Refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air-conditioning of buildings and automobiles.  Question 8. Why Is A Compressor Used In Refrigeration?

Answer : The compressor does exactly as its name says: it compresses the refrigerant. The compressor receives low pressure gas from the evaporator and converts it to high pressure gas. As mentioned earlier, as the gas is compressed, the temperature rises. The hot refrigerant gas then flows to the condenser.  Question 9. What Is Auto Refrigeration? Answer : Auto-refrigeration is a process where an unintentional and/or uncontrolled phase change of a hydrocarbon from a liquid state to a vapor occurs, resulting in a very rapid chilling (refrigeration) of the liquid containing local equipment and/or piping.  Question 10. How Does A Refrigerant Compressor Work? Answer :   

The compressor constricts the refrigerant vapor, raising its pressure, and pushes it into the coils on the outside of the refrigerator. When the hot gas in the coils meets the cooler air temperature of the kitchen, it becomes a liquid. The refrigerant absorbs the heat inside the fridge, cooling down the air.

 Question 11. Why Capacity Of Air Conditioner Is Measured In Tons? Answer : A 4 ton air conditioner is one that can remove 48,000 BTUs of heat per hour from the house. For most people, though, 4 tons means 8000 pounds. (A BTU is a British Thermal Unit, approximately the amount of heat you get from burning one kitchen match all the way down.)  Question 12. What Is The Meaning Of 1 Ton Of Ac? Answer : A ton, as used in the HVAC field, is a term that describes how much heat the AC unit can remove from a home in one hour. The measurement for heat is the British thermal unit (BTU). One ton of air conditioning can remove 12,000 BTUs of air per hour.  Question 13. What Is An Air Conditioning Ton? Answer : A ton is the cooling capacity of an air conditioning system. One ton is equal to the amount of heat required (288,000 Btu) to melt one ton of ice in a 24-hour period. A one-ton air conditioner is rated at 12,000 Btu per hour (288,000/24). A two-ton unit would be rated at 24,000 Btu per hour.

 Question 14. What Is Btu? Answer : The British thermal unit (Btu or BTU) is a traditional unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. ... Heat is now known to be equivalent to energy, for which the metric unit is the joule; one BTU is about 1055 joules.  Question 15. What Is The Meaning Of Btu In Air Conditioners? Answer : Btu – British Thermal Unit (Btu) is the international measure of energy. A Btu is the amount of heat needed to raise 1 (one) pound of water by 1(one) degree Fahrenheit. In HVAC industry, Btu's measure the quantity of heat a conditioning unit can remove from a room per hours. One BTU per hour is equal to 0293 watts.  Question 16. What Is Cfm & Infiltration? Answer : The infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (CFM) or liters per second (LPS). The air exchange rate, (I), is the number of interior volume air changes that occur per hour, and has units of 1/h.  Question 17. What Is The Hvac System? Answer : While the Energy Center usually tries to avoid the use of acronyms, HVAC is in common use in the heating and cooling industry. It stands for "heating, ventilation and air conditioning," three functions often combined into one system in today's modern homes and buildings.  Question 18. What Does A Hvac Engineer Do? Answer : An HVAC engineer's job duties can include the design, installation, maintenance, and repair of heating, ventilation, air conditioning, cooling, and refrigeration systems.  Question 19. What Is Psychometry? Answer : Psychometry is a psychic ability in which a person can sense or "read" the history of an object by touching it. Such a person can receive impressions from an object by holding it in his/her hands or, perhaps, touching it to the forehead.

 Question 20. What Are The Types Of Air Conditioning Systems? Answer : Types of Air Conditioning Systems The choice of which air conditioner system to use depends upon a number of factors including how large the area is to be cooled, the total heat generated inside the enclosed area, etc.    

Window Air Conditioner. Split Air Conditioner. Packaged Air Conditioner. Central Air Conditioning System.

 Question 21. How The Lighting Load Is Calculated? Answer : The standard method consists of three calculation steps: General lighting VA load. When calculating branch circuits and feeder/service loads for dwellings, include a minimum 3VA per sq ft for general lighting and general-use receptacles [220.12]. When determining the area, use the outside dimensions of the dwelling.  Question 22. What Is The Function Of Ahu? Answer : An Air Handling Unit (AHU) is used to re-condition and circulate air as part of a heating, ventilating and air-conditioning system. The basic function of the AHU is take in outside air, re-condition it and supply it as fresh air to a building.  Question 23. How Does The Ahu Work? Answer : An air handler is usually a large metal box containing a blower, heating or cooling elements, filter racks or chambers, sound attenuators, and dampers. Air handlers usually connect to a ductwork ventilation system that distributes the conditioned air through the building and returns it to the AHU.  Question 24. What Is The Purpose Of Air Handling Units? Answer : An air handler, or air handling unit (often called an AHU), is used to condition and circulate air as part of an HVAC system. An air handler usually contains a blower, heating or cooling elements, filter racks or chambers, sound attenuators, and dampers.

 Question 25. Where The Fcu’s Are Used? Answer : A fan coil unit is a simple device consisting of a heating or cooling coil and fan. It is part of an HVAC system found in residential, commercial, and buildings. Typically a fan coil unit is not connected to ductwork and is used to control the temperature in the space where it is installed, or serve multiple spaces.  Question 26. What Is The Fcu? Answer : A Fan Coil Unit (FCU) is a simple device consisting of a heating and/or cooling heat exchanger or 'coil' and fan. It is part of an HVAC system found in residential, commercial, and industrial buildings.  Question 27. What Is The Meaning Of Fahu? Answer : FAHU is the abbreviation used for FRESH AIR HANDLING UNIT. These are usually centralized units employed to induce fresh air quantities to the confines spaces. They come into picture wherever there are limitations to fresh air intake either directly or through AHUs.  Question 28. What Is An Air Conditioner Condenser? Answer : The AC condenser is a very important component found on virtually all modern automotive AC systems. Its primary function is to convert the refrigerant coming from the compressor from a high temperature, high pressure vapor into a high pressure liquid through condensation.  Question 29. how Does A Condenser In A Refrigerator Work? Answer : In the refrigeration cycle, there are five basic components: fluid refrigerant; a compressor, which controls the flow of refrigerant; the condenser coils (on the outside of the fridge); the evaporator coils (on the inside of the fridge); and something called an expansion device.  Question 30. What Is The Main Function Of A Condenser? Answer : In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant.

 Question 31. How Does A Condensing Unit Work? Answer : Inside the condenser, the refrigerant vapor is compressed and forced through a heat exchange coil, condensing it into a liquid and rejecting the heat previously absorbed from the cool indoor area. The condenser's heat exchanger is generally cooled by a fan blowing outside air through it.  Question 32. What Are The Types Of Condensers? Answer : The three main types of condensers used in general refrigeration systems are: 1. air-cooled. 2. water-cooled. 3. evaporative.  Question 33. What Is A Rotary Air Compressor? Answer : A rotary-screw compressor is a type of gas compressor that uses a rotary-type positivedisplacement mechanism. They are commonly used to replace piston compressors where large volumes of high-pressure air are needed, either for large industrial applications or to operate high-power air tools such as jackhammers.  Question 34. What Is A Gas Compressor Used For? Answer : A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe.  Question 35. What Is The Use Of Compressor In Refrigeration? Answer : The compressor does exactly as its name says: it compresses the refrigerant. The compressor receives low pressure gas from the evaporator and converts it to high pressure gas. As mentioned earlier, as the gas is compressed, the temperature rises. The hot refrigerant gas then flows to the condenser.

Bearing Interview Question

 Question 1. If You Have A New Bearing That Has Been Used, But Is Pretty Dirty, What Can You Do To Use It Again? Answer : Hand wash, and try not to spin it. Never wash double shield bearings, only wipe them off then apply lubricant before wrapping and storing.  Question 2. Besides Storing Bearings On The Shelf, What’s The “correct” Way To Store Them? Answer : Keep bearings in a clean, dry location, and watch temperature changes as drastic changes can harm the bearing if any moisture is present. Handle bearings as little as possible, as your fingerprints can promote rusting. Take care not to drop or handle them roughly, they are precision components. Another best practice is to store them by keeping the oldest at the front, and always using the oldest bearing first.  Question 3. I Understand Lubrication Is Essential, But What Is Its Main Role? Answer : Lubricant is used to establish and maintain a micro-thick separating film between rotating and static parts, so that the bearing can perform well, have long life, and keep from being damaged.  Question 4. Is Getting The Correct Type Of Lubricant Really Important? Answer : Yes, improper lubrication is responsible for approximately 43% of bearing failure – that’s a lot! Application specific grease or oil is important, as is lubricating frequency, quantity, and viscosity. Be sure to re-lube at proper intervals, and beware lubricant contamination. And, take note that over-lubrication of bearings used in high heat applications can be just as harmful as insufficient lubrication.  Question 5. Can Seals Be Used In Place Of Shields On A Ball Bearing? Answer : Not if you want to avoid problems. A shield provides a clearance between the inner and outer race, whereas a seal is attached to the inner race and could cause problems rubbing on the inner race, depending on the speed, heat, and starting torque of the machine.  Question 6. How Can I Determine If A Bearing Is Failing? Answer :

Three main indicators – excessive noise, heat, and/or vibration. If these are present more than expected, you can be pretty certain that a bearings is failing.  Question 7. Are There Any Common Improper Methods Of Mounting Or Installation? Answer : A couple main ones here. One is contaminating the bearing during installation. The other is applying force on the incorrect ring, as it should only be applied to the press fitted ring.  Question 8. If My Work Space Is Dirty, How Can I Take Care To Install A New Bearing Without Messing It Up From The Git-go? Answer : It’s understandable, after you’ve taken the time and care to properly store your bearings, that you would want to be sure to install them in a clean environment. But, that’s tricky. Clean the work bench area and the tools you will use on the new bearing, and keep away any linty clothes. Keep the bearing on its original wrapper or some clean paper when working on it. Don’t let the bearing sit on a dirty surface, even for a short time, or you’ll risk contamination and early failure. And, remember bearings should not be washed, except for oil mist or circulating oil system.  Question 9. Will A Stainless Steel Bearing Protect Against Rust? Answer : Not to the extent you might think. Stainless steel is not rust proof. It is corrosion resistant and will rust in corrosive environments over time, but at a much slower rate than chrome alloy steel.  Question 10. What Is A Good Waterproof Seal? Answer : Bearing seals are designed to retain the lubrication inside the bearing, and most are considered water-repellent, but they won’t prevent water from entering the bearing if it is submerged. If the bearing must operate while submerged in a liquid, use a ceramic hybrid or full ceramic bearing.  Question 11. What Does “radial Play” Mean? Answer : Radial Play refers to the fit or clearance of the balls within the bearing. The normal range is from C2 to C5, with C2 being the tightest fit (not much room for expansion of the balls or misalignment) and C5 being the loosest (allowance for some expansion as the bearing heats up or misalignment of the application).

 Question 12. Can I Flush Out A Lubricant And Use Another? Answer : You would need a prescribed flushing agent, and a properly environmentally controlled environment in a controlled area. The bearing would have to be thoroughly dried post flush, and lubricated with the correct amount and type of grease. Short answer is yes, with some extra effort.  Question 13. What Methods Of Payment Do You Accept? Answer : Bearing Service accepts cash, VISA, MasterCard, American Express, Discover, Diners Club and company purchase orders on open accounts, subject to credit approval.  Question 14. What Shipping Methods Do You Use? Answer : Bearing Service will ship your order anywhere in the United States or abroad. We use United Parcel Service and Federal Express for lighter shipments, and a variety of motor freight carriers for heavy shipments. We will ship same-day on in-stock items for standard shipment. UPS and Fed-Ex offer standard service, second-day, and next-day shipping.  Question 15. Where Can I Find Product Specifications On Bearings And Other Products? Answer : The best method for obtaining this information is to contact one of our experienced sales reps. we have extensive resources available to us. If the sales person cannot immediately answer your question, we will research it and respond in a timely manner.  Question 16. Do You Have A Catalog? Answer : Bearing Service does not publish a catalog for use by our customers. We assume the job of helping our customers identify and find the products they need, rather than you spending hours digging through a catalog that only has a small portion of the manufacturer's product line. We can provide the manufacturer's catalog for any line we represent, giving you information on the full line of merchandise.  Question 17. What Does Bearing Service Manufacture? Answer :

Bearing Service is a distributor. We do not manufacture the products we sell, but our shops can machine, fabricate, and customize a variety of products to meet your maintenance needs.  Question 18. Do You Provide Training For Your Customers? Answer : Bearing Service will work with your staff to provide product training for your maintenance and purchasing people. We will work with various manufacturers to make available their product training seminars and courses, or we can work with you to customize a seminar for your needs.

Mechanical Fitter Interview Questions  Question 1. Define Valve? Answer : Valve is a Mechanical flow control element in the process.  Question 2. What Are Types Of Valves? Answer :              

Gate Valve Globe Valve Ball valve Butterfly Valve Needle Valve Plug Valve Diaphragm Valve Non-Return Valve Knife Edge Valve Drain Valve Float Valve Flush Bottom Valve Pinch Valve Pen Stack Valve etc.

 Question 3. Explain The Valve Parts? Answer : Gate Valve – Body, Bonnet, Seat, Gate, Stem, Hand Wheel, Gland Bush, Gland Flange, Gland Bolt and Nuts. Hand Wheel lock nut.

Ball Valve – Body , End Piece , Ball , Stem , Seal , Seal Follower , Seat , Lock Nut , Handle Gland Packing , Gland Flange , Gland Stud and nut. Globe Valve – Body , Bonnet , Seat , Plug , stem , Hand Wheel , Lock Nut ,Gland Packing , Gland Flange , Gland Stud and nut. Butterfly – Body , Disc , Stem , Seat ring , Seat ring holder , Bush , End cover , Hand Wheel or Gear Box , Gland Bush , Gland Packing , Gland Flange , Gland Stud and nut.  Question 4. What Are The Types Of Gaskets? Answer :          

CAF – Compressed Asbestos Fiber Filled Gasket Semi Metallic Gasket Metallic Gasket Rubber Gasket Teflon Gasket Spiral Wound Gasket RTJ – Ring Type Joint Graphite Gasket Impregnated Gasket Graf oil Gasket

 Question 5. What Is Gasket? Where It Is Used? Answer : It is sealing member between two flanges. Uses: 1. 2. 3. 4. 5. 6.

Water Line, Gas Line, Air Line used CAF Gasket. RTJ – High Pressure Line. Chemical Line – Rubber Gasket and Teflon Gasket. Steam Line – Semi Metallic, Metallic and Graphite. Impregnated Gasket – Valve Sealing Gasket. Spiral Wound – Steam Line.

 Question 6. What Is Flange? Types Of Flanges? Answer : Flanges used to connect both lines (Fluid, Gas, Oil, Water….)     

Thread Type Flange Modified Flange Weld Neck Flange Slip On Flange Goose Neck Flange

    

Socket Weld Flange Stepped Flange Spade Flange Spectacle Flange Blind Flange

 Question 7. What Is Gland Packing? Uses Of Gland Packing? Answer : Gland packing is a Sealing member between two moving parts or stationary. It is used for arrest the leak through shaft various lines. 1. 2. 3. 4. 5.

Teflon Gland packing Graphite Gland packing Carbon Gland packing Virgin PTFE Gland packing Graf oil Gland packing

 Question 8. What Are Prv And Psv? Answer :  

PRV (Pressure Relief valve) release excessive more than set point, released fluid re circulated. PSV (Pressure Safety Valve) released pressure more than set point to safe the equipments.

 Question 9. Give The Parts Name Of Psv? Answer :               

Body Bonnet Nozzle Disc Disc Holder Stem Blow down ring Blow down ring lock screw Spring Bottom Plate Spring Spring Top Plate Control Screw Lock Nut Cap Gasket

 Question 10. What Is The Use Of Spade, Spectacle, And Blind?

Answer : SPADE- Give space between two flanges and give flow through the spade. SPECTACLE – Combination of SPADE and BLIND and both option done in one flange. BLIND – Used for close the line.  Question 11. What Is Ppe? Answer : PPE- Personal Protective Equipment E.g.) Helmet, Boiler Shout, Safety Goggles, Safety Shoe, Gloves, Dust Mask etc...  Question 12. What Is Heat Exchanger? What Are The Types Of Heat Exchanger? Answer : It is an Equipment to use for Exchange the heat(Cooling or Heating purpose) Types:      

Fixed Tube Heat Exchanger Floating Tube Heat Exchanger U Tube Exchanger Plate Type Exchanger Fin Fan Cooler Heat Exchanger Bridge Lock Exchanger

 Question 13. Explain The Following Valves Shell And Seat Testing? Answer :     

Ball Valve Gate Valve Globe Valve Butterfly valve Plug valve

Shell Test of above valves:Testing flange to be fixed on both sides. Pressurized one side under the valve partial open condition as per the standard. Check the leakage through body, Bonnet sealing area, Gland packing area. Seat Test of above valves:-

Testing flange to be fix on one side of the valve. Pressurized the valve under fully closed condition as per the standard. Check the leakage through Seat in opposite side. Follow the same procedure while checking the another seat except Globe and Butterfly.  Question 14. What Are The Testing Mediums Used For Testing? Answer : Water, DM Water, Air, Kerosene, Oil, Soap water.  Question 15. What Is Steam Trap And Gas Trap? Answer : Steam trap using for removal of Water from Steam. Gas trap using for removal of water from gas.  Question 16. What Is The Use Of Vacuum Breaker? Answer : It is used to remove Vacuum (Air Bubbles) from Water line.  Question 17. What Is The Use Of Ejector? Answer : Ejector is used to create Vacuum for process.  Question 18. Define Non Sparking Tools? Answer : Non Sparking tools used in Gas, Oil and Chemicals. E.g. Brass hammer, Brass Wedge, Brass Spanner, Copper hammer, Copper rod , Brass rod , Brass chisel , Rubber hammer , Nylon hammer.  Question 19. What Is Strainer? Answer : Strainer is a control element to arrest dust from flowing fluids.  Question 20. What Is Work Permit System? Answer :

Work Permit is an Authority for doing work in a process plant. Types: Cold Work Permit- Without Sparking, Without Heat etc. Hot Work Permit- With heat (Grinding, Cutting, Welding).

Power Transmission Interview Questions  Question 1. What Is Meant By A Belt Drive? Answer : When power is driven from driver pulley to driven pulley by means of belt , it is known as belt drive. In open belt drive both the pulleys run in the same direction and in cross belt drive both the pulleys run in opposite direction to each other.  Question 2. What Is The Material Of Belts? Answer : Belts are generally made by canvas ,rubber, leather and steel.  Question 3. What Are The Reasons For Slipping Of Belt? Answer :   

The belt is loosely fitted. Overloading on belt drive. Misalignment of pulleys.

 Question 4. What Are The Points To Be Noted When Selecting A Belt? Answer :    

Load of the machine. Speed of the machine. Capacity of machine. Atmosphere of the climate.

 Question 5. What Are The Uses Of Jockey Pulley? Answer : Jockey pulley is used to increase the contacting area in between the belt and pulley and also used to press the belt for giving tension.

 Question 6. Define Crowning In Belt Drive? Answer : The outer surface or face of rim of the pulley is made in convex form to keep the belt in center when it is in movement, it is called crowning.  Question 7. What Is Dressing In Belt Drive? Answer : To avoid slip or creep, the resin powder or paste is poured in between the outer surface of pulley and belt for increasing the tension is called dressing.  Question 8. Write Short Notes On Creep And Slip In Belt Drive? Answer :  

The movement of belt upon the face of rim or outer surface of driver and driven pulleys within the area of arc of contact is called creep in belt drive. If the belt is loosely fitted on pulleys, it slips down which is called slip in belt drive.

 Question 9. What Are The Rules For Belt Drives? Answer :    

The distance between two pulleys should not be less than three times the diameter of the larger pulley. The slack side should be uppermost which may increase the arc of contact. The ratio of diameter of both the pulleys should not exceed 6:1. If necessary ,a jockey pulley should be used to minimize the slip.

 Question 10. What Are The Advantages And Disadvantages Of V Belt? Answer :  

The main advantages of V belt are it has more gripping power, long life and it occupies less space. Disadvantages are it is not fit for long distances and cross belt drive.

 Question 11. What Are The Functions Of Gears? Answer :     

To change the direction of rotation To change the speed. To change the plane directions. To transmit power. To give positive drive.

 Question 12. What Do You Mean A Worm Drive? Answer : Worm drive consists of a worm and worm wheel and the worm wheel is always driven by the worm. It is suitable for heavy loads and also for speed reduction.  Question 13. What Is Spur Gear? Answer : It is a common type of gear having teeth in straight. It is used to transmit the motion on parallel shafts and used for all general purpose for transmitting motion.  Question 14. What Is The Difference Between Addendum And Dedendum? Answer :  

Addendum is the distance from the top of tooth to the pitch circle. Dedendum is the distance from the root to the pitch circle of gear tooth.

 Question 15. Define Chordal Thickness? Answer : It is distance in straight line from tooth to tooth along the pitch circle.  Question 16. What Is Module? Answer : It is the ratio between the pitch diameter and the number of teeth in the gear.  Question 17. Define Diameteral Pitch? Answer : Diameteral pitch is the ratio between the number of teeth of a gear and the pitch circle diameter.  Question 18. Which Gears Are Used To Connect The Shafts Lying In The Same Plane? Answer : Spur gears, Helical gears, Internal gears and Herringbone gears  Question 19. Differentiate Between Herringbone Gears And Helical Gears?

Answer : 



Herringbone Gears . Double helical gears are known as Herringbone gears. These gears have teeth in series on both sides from the centre in the inclined position to the axis. These type of gears are used to transmit motion at high speed with heavy load without producing noise. Helical Gears. These type of gears have teeth in series of single way in an inclined position. Helical gears are used to transmit the motion at high speed without producing noise.

 Question 20. Which Gears Are Used To Connect The Shafts Which Intersect At Same Angle? Answer : Bevel gears and angle gears.  Question 21. Which Gears Are Used To Connect The Shafts At An Angle But Lying In The Same Plane? Answer :  

Spiral gears Worm and worm wheel

 Question 22. What Do You Mean By Bevel Gear? Answer : These gears have intersecting axis. Bevel gears are used to connect shafts which are not parallel and when their axis meet at an angle and found with straight, helical and spiral teeth.  Question 23. Explain Rack And Pinion ? Answer : Rack is a flat bar having straight teeth in series .It is meshed with a pinion having straight teeth like spur gear. These type gears used in carriage of lathe and milling machine table.  Question 24. Explain Briefly About Friction And Anti-friction Bearings? Answer : 



Friction bearings. This type of bearings contact that shaft directly such as bush bearing ,journal bearing etc. These bearings generally made of cast iron ,brass and gun metal. Anti-friction bearings. These type of bearings have rolling elements such as balls, rollers etc.

 Question 25. Why Is The Bearing Tinned Before Refilling? Answer : While removing the damaged lining it helps to melt the lining at low temperature and it helps to spread over the molten metal on the bearing surface.  Question 26. What Are The Functions Of A Bearing? Answer :   

To guide the shaft. To support the shaft. To give free rotation to the shaft.

 Question 27. Where Are The Following Bearings Used? Answer :  

Ball bearing is generally used on high speed with light load because it has point contact. Roller bearing is generally used on high speed with heavy load because it has line contact.

 Question 28. What Is The Use Of Taper Roller Bearing? Answer : A taper roller bearing is used to carry heavy loads because it has taper rollers instead of plain cylindrical rollers.  Question 29. What Is The Application Of White Metal Bearing? Answer : It is generally used on high speed with light load because its bearing metal controls the heat.  Question 30. What Are The Reasons Of Over Heating On Anti-friction Bearings? Answer : The main reasons are, inadequate lubrication ,overloading ,miss-alignment and bearing in defective condition.  Question 31. What Are The Various Types Of Bearings? Answer :





Bush Bearing. It is a plain cylindrical bearing made of brass , gun metal ,cast iron etc. Its inner bore is finished and made running fit to the shaft. It is generally used on low speed shafts carrying light load. Ball bearing. It consists of outer race, inner race, steel balls and cage. The balls are rolling themselves in the tracks between the outer and inner races ,bearing is fitted on shaft while its outer portion is fixed in housing .Balls have point contact and are free in the races,friction makes balls to rotate.

 Question 32. What Is Journal Bearing And Mention Its Use? Answer : It is a split bearing having two halves which are made of brass, gun metal, etc. Its outer ends have collar on both sides. IT is fitted in the housing generally made of cast iron. It is used where the supporting pressure of the bearing is at right angle to the shaft axis.  Question 33. What Are The Advantages Of Anti-friction Bearing Over A Friction Bearing? Answer :     

For reducing wear and tear. For saving the power consumption. For easy setup. For smooth running of machine. For running at slow and high speed carrying light and heavy loads.

 Question 34. What Is A Cam? Answer : A cam is a cylinder, plate or other solid with curved outline which is designed to convert rotary motion into timed irregular motion on the follower which is in contact with it.ie,cams rotary motion can be changed to reciprocating motion.  Question 35. What Are The Main Types Of Cams? Answer : There are two main types of cams used in industries,  

Radial cam. On this cam the follower operates in a plane perpendicular the axis of the camshaft which is raised and lowered as the cam revolves. Cylindrical Cam. On this cam the follower oscillates in a plane parallel with the axis of the camshaft .

 Question 36. Name Different Types Of Shafts Used In Industry? Answer :

Commonly four types of shafts are used in industry:    

Main shaft Counter shaft Crank shaft Splined shaft.

 Question 37. What Are The Different Types Of Cam Motions? Answer : Uniform or constant motion,Harmonic motion, Uniform accelerate and retarded motion.  Question 38. Name Different Types Of Cam Followers? Answer : Commonly used followers are, Pointed , Flat faced, Roller and Spherical faced.  Question 39. Explain About A Screw Jack? Answer : A Screw jack consists of a body and a square threaded screw rod. Its screw rod has a head and a revolving pad. This screw rod acts on both directions according to the action of the lever attached with ratchet arrangement with the handle. It is used to lift the loads therefore it is mostly used by motor mechanics.  Question 40. Explain Briefly The Use Of Clutch? Answer : Clutch is used to connect and disconnect the driving and driven units of a machine. It does the function when machine speed is changed after stopping the driving unit.  Question 41. What Do You Mean A Coupling? Answer : It is a device used to connect two shafts. These are generally used to increase the length of shafts.  Question 42. What Is A Flange Coupling? Answer : It is very common type of coupling used to connect the shafts by means of two flanges. Two cast iron flanges are fitted with key to the ends of the two shafts to be connected and fastened together by means of bolts and nuts.

 Question 43. Explain About Universal Coupling? Answer : It is used to connect two shafts whose axis are not in line with each one center block, two pins and two pins and two collars with lock pins. The forks are fitted with key on the ends of two shafts and then joined to a center block having two arms at 90 degree to each other. This coupling does the function on the action of its two pins. It does not work well if the angle between the two shafts is more than 45 degree.  Question 44. What Is A Flexible Coupling? Answer : It connects the shafts with soft materials such as rubber, leather, canvas etc. It adjusts the little misalignment and controls the vibrations also. It is generally used electric pumps.  Question 45. Explain About Pulley Block? Answer : Pulley block is a block in which two or three group of pulleys are used with a rope to lift and heavy loads. The load is tied in the hook of the movable block and the effort is applied at the end of the rope which comes through the fixed pulley block.  Question 46. Write About Muff Coupling? Answer : It is a hollow piece which is used with key to connect the shafts. It may be found in cylindrical muff,half lap muff or split muff type. A gib head key or a saddle key is inserted between the coupling and shafts through out for connecting the shafts.  Question 47. Explain About Hydraulic Jack? Answer : It consists of a cylinder and ram. The oil is forced into the cylinder. The load is lifted by this jack according to the pressure of the oil. In its working system the oil is filled through the oil plug in the oil reservoir. It has a tube at the lower en d and a non return valve. When the lever is operated up and down, plunger moves up in the tube supplying the oil and it down the non return valve which allow the oil into the cylinder which causes the ram raises. The ram raises according to the pressure of the oil which lift the load accordingly.  Question 48. What Is A Chain Block? Answer :

It consists of two grooved pulleys which are fixed side on the same spindle having chain also. While another pulley is fitted with clamp in which a lifting hook is provided. One chain connects the hanging pulley. When a chain is pulled by hand then all the pulleys start functioning and the hook carries the load. In this way the load is lifted to a required height.  Question 49. What Is The Formula To Find Out The Length Of A Belt In An Open Belt Drive? Answer : L = 2C + 1.57 (D + d) + (D-d)2 /4C  Question 50. What Is The Formula To Find Out The Length Of A Belt In A Closed Belt Drive? Answer : L = 2C + 1.57 (D +d ) + (D+d)2/ 4C  Question 51. How To Calculate The Number Of Teeth In A Gear If Given The Module And Pitch Circle Diameter? Answer :  

Pitch = Module* 3.14 (pie value) Number of teeth = Pitch circle diameter/ pitch

 Question 52. What Are Standard Pipe Threads? Answer : Pipe threads are grouped in certain ranges such as 1/4” to 3/8” pipe threads have 19 T.P.I , ½ “ to 7/ 8” pipe threads have 14 T.P.I, 1” and above size pipe threads have 11 T.P.I . Pipe threads may be either straight or tapered.  Question 53. Name Different Pipe Fitting Accessories? Answer : Commonly used pipe fitting accessories are : Socket, Reducing socket, Cross, Union, Stop valve, Elbow, Union, Plug, Flange, Tee.  Question 54. What Is The Use Of Chain Wrench In Pipe Fitting? Answer : It is used to hold the pipe firmly and it is fit for rotation on both ways.

 Question 55. Explain About Common Types Of Pipe Materials And How Are Pipes Specified? Answer : Pipes are commonly made of cast iron , steel, copper, lead, zinc, galvanized iron(G.I) wrought iron , aluminium and also cement and plastic pipes are used. Generally pipes are specified by the length, material, bore size.  Question 56. Describe The Methods Of Protecting Leakage At The Pipe Joint? Answer : 



Threads joints should be fixed applying red lead, white lead, dry point etc. in the threads, bound the pipe threads using twine and tightened them fully with a suitable wrench. Flanged joint should be fixed using a washer of rubber, leather, card board or soft metal in metal in between the inner sides of both the flanges.

 Question 57. What Are The Different Types Of Tools Used In Pipe Fittings? Answer : Generally tools used in pipe fittings are Pipe vice, Pipe wrench, Pipe die, Pipe tap, Chain wrench, Chisel, Hammer, Reamer and Pipe cutter.  Question 58. Explain Briefly The Uses Of Pipe Vice And Pipe Wrench ? Answer :  

Pipe vice. It is used to hold the pipe firmly while cutting, threading etc. Pipe wrench. It is used fir tightening and loosening the pipes.

 Question 59. Explain About Spigot And Socket Joint? Answer : This joint is generally used to connect cast iron pipes which are buried in ground .This is also suitable for straight pipe line carrying water and this joint has less rigidity.  Question 60. What Do You Meant By Expansion Joint? Answer : This joint is used to carry the piping system at high pressure. This joint is provided with gland and stuffing box which make the joint perfectly steam tight. To prevent leakage asbestos packing is provided.

Machine Design Interview Questions  Question 1. Define Ductility? Answer : It is the property of the material enabling it to be drawn into wire, with the application of tensile force. It must be both strong and plastic. It is usually measured in terms of percentage elongation and reduction in area, (e.g.) Ni, Al, and Cu.  Question 2. Define Fatigue? Answer : When a material is subjected to repeated stress, it fails at stresses below the yield point stress; such type of failure of the material is called fatigue.  Question 3. Define Factor Of Safety? Answer : The ratio between maximum stresses to working stress is known as factor of safety. Factor of safety = Maximum stress /Working stress  Question 4. Define Endurance Limit? Answer : Endurance limit is the maximum value of completely reversed stress that the standard specimen can sustain an infinite number (106) of cycles without failure.  Question 5. What Is Impact Load? Answer : If the time of load application is less than one third of the lowest natural period of vibration of the part, it is called an impact load.  Question 6. What Are The Various Phases Of Design Process? Answer : The various phases of design process are: 1. Recognition of need. 2. Definition of problem

3. 4. 5. 6.

Synthesis Analysis and optimization Evaluation Presentation

 Question 7. What Are The Different Types Of Loads That Can Act On Machine Components? Answer : Different loads on machine components are: 1. 2. 3. 4.

Steady load. Variable load. Shock load Impact load.

 Question 8. What Are The Factors Affecting Endurance Strength? Answer : Factors affecting endurance strength are 1. 2. 3. 4. 5.

Load ii. Surface finish Size Temperature Impact Reliability

 Question 9. What Are The Types Of Variable Stresses? Answer : Types of variable stresses are: 1. Completely reversed or cyclic stresses 2. Fluctuating stresses 3. Repeated stresses  Question 10. Differentiate Between Repeated Stress And Reversed Stress? Answer : Repeated stress refers to a stress varying from zero to a maximum value of same nature. Reversed stress of cyclic stress varies from one value of tension to the same value of compression.  Question 11. What Are The Types Of Fracture?

Answer : The two types of fracture are 1. Ductile fracture 2. Brittle fracture  Question 12. Distinguish Between Brittle Fracture And Ductile Fracture? Answer : In brittle fracture, crack growth is up to a small depth of the material. In ductile fracture large amount of plastic deformation is present to a higher depth.  Question 13. Define Stress Concentration And Stress Concentration Factor? Answer : Stress concentration is the increase in local stresses at points of rapid change in cross section or discontinuities. Stress concentration factor is the ratio of maximum stress at critical section to the nominal stress.  Question 14. Explain Size Factor In Endurance Strength? Answer : Size factor is used to consider the effect of the size on endurance strength. A large size object will have more defects compared to a small one. So, endurance strength is reduced. If K is the size factor, then Actual endurance strength = Theoretical endurance limit x K  Question 15. Explain Griffith Theory. (or) State The Condition For Crack Growth? Answer : A crack can propagate if the energy release rate of crack is greater than crack resistance.  Question 16. What Are The Modes Of Fracture? Answer : The different the modes of fractures are: 1. Mode I (Opening mode) – Displacement is normal to crack surface. 2. Mode II (Sliding mode) – Displacement is in the plane of the plate.

3. Mode III (Tearing mode) – Out of plane shear.  Question 17. What Are The Factors To Be Considered In The Selection Of Materials For A Machine Element? Answer : While selecting a material for a machine element, the following factors are to be considered 1. 2. 3. 4.

Required material properties Manufacturing ease Material availability Cost

 Question 18. What Are Various Theories Of Failure? Answer : The failure theories are: 1. Maximum principal stress theory. 2. Maximum shear stress theory. 3. Maximum principal strain theory.  Question 19. List Out The Factors Involved In Arriving At Factor Of Safety? Answer : The factors involved in arriving at factor of safety are: 1. 2. 3. 4.

Material properties Nature of loads Presence of localized stresses Mode of failures

 Question 20. Give Some Methods Of Reducing Stress Concentration? Answer : Some of the methods are: 1. 2. 3. 4.

Avoiding sharp corners. Providing fillets. Use of multiple holes instead of single hole Undercutting the shoulder parts.

 Question 21. Explain Notch Sensitivity. State The Relation Between Stress Concentration Factor And Notch Sensitivity?

Answer : Notch sensitivity (q) is the degree to which the theoretical effect of stress concentration is actually reached. The relation is, Kf = 1 + q (Kt-1)  Question 22. What Are The Factors That Affect Notch Sensitivity? Answer : The factors effecting notch sensitivity are: 1. 2. 3. 4. 5.

Material Notch radius Size of component Type of loading Grain Structure

 Question 23. What Is The Use Of Goodman & Soderberg Diagrams? Answer : They are used to solve the problems of variable stresses.  Question 24. Define Mach Inability? Answer : It is the property of the material, which refers to a relative ease with which a material can be cut. It is measured in a number of ways such as comparing the tool life for cutting different material.  Question 25. What Is An S-n Curve? Answer : N curve has fatigue stress on ‘Y’ axis and number of loading cycles in ‘X’ axis. It is used to find the fatigue stress value corresponding to a given number of cycles.  Question 26. What Is Curved Beam? Answer : In curved beam the neutral axis does not coincide with the centroidal axis.  Question 27. Give Some Example For Curved Beam? Answer :

C frame, crane hook.  Question 28. What Is Principle Stress And Principle Plane? Answer : A plane which has no shear stress is called principle plane the corresponding stress is called principle stress.  Question 29. Write The Bending Equation? Answer : The bending moment equation is, M/I = f/y= E/R, Where, M – Bending moment (M is in N-mm) I - Moment of inertia about centroidal axis (I is in mm⁴) f – Bending Stress (f is in N/mm²) y - Distance from neutral axis (y is in mm) E - Young’s modulus (E is in N/mm²) R - Radius of curvature (R is in mm)  Question 30. Write The Torsion Equation? Answer : The torsional equation is, T/J = q/r = GӨ/L Where, T – Torsional moment (T is in N-mm) J - Polar moment of inertia (J is in mm⁴) q – Shear stress in the element (q is in N/mm²) r - Distance of element from centre of shaft (r is in mm) G- Modulus of Rigidity (G is in N/mm²) Ө – Angle of twist (Ө is in radians) L – Length of the shaft (L is in mm)  Question 31. What Are The Common Profiles Used For Splines In Machine Elements? Answer : The profiles used for splines in machine elements are straight sided splines, triangular splines and in volute splines.

 Question 32. What Type Of Threads Are Used For Pressure Tight Joints And For Power Transmission? Answer : Pipe threads are used for pressure tight joints and square threads for power transmission.  Question 33. How Computer Helps In Designing? Answer : Computer is able to store lot of information and same can be retrieved fast. It performs calculations very fast. The design can be visualized on screen and any alterations made and its effects clearly seen. Thus optimum designs can be achieved much faster and these are thoroughly tested from all angles.  Question 34. Can You Tell Something About Hazop Study? Answer : In Hazop (Hazards and operatibility) study each and every conceivable process deviation from normal operating condition of a system having identical design intention, is thoroughly analysed for causes and consequence and required action plan to mitigate hazard/operability problems are suggested on the basis of available protective system.  Question 35. Why Slenderness Ratio Is Considered In Design Of Members? Answer : When length of the member is increased, the member may fail due to buckling even though the member is symmetrical in all respects and the load is concentric.  Question 36. What Do You Mean By Allowance In Limits And Fits? Answer : Allowance in limits and fits refers to maximum clearance between shaft and hole.  Question 37. A Wire Rope Is Designated As 6 X 19 Standard Hoisting. What Do The Numbers 6 X 19 Represent? Answer : Number of strands x number of wires in each strand.  Question 38. Why A Sleeve Is Fitted On A Ball Bearing? Answer :

To prevent relative axial movement between the shaft and the bearing.  Question 39. What Is The Constant Factor In Case Of R-10 Series Of Preferred Numbers? Answer : 1.25  Question 40. On What Basis A Transmission Shaft Subjected To Bending Loads Must Be Designed? Answer : Maximum shear stress theory.  Question 41. In Designing A Clutch Plate, What Assumption Is Made? Answer : Uniform wear condition is assumed because it leads to safer design.  Question 42. The Critical Speed Of Rotating Shaft Depends Upon What? Answer : Mass and stiffness.  Question 43. What Is The Empirical Formula Used To Give The Number Of Bolts In Flange Coupling? Answer : n = 0.2d + 3  Question 44. How The Size Of The Gearis Usually Specified? Answer : By pitch circle diameter.  Question 45. While Taking A Turn, What Action Differential Makes? Answer : An increase in the speed of the outer wheel.  Question 46. Rankine’s And Guest’s Theory Of Failure Are Applicable For What Materials?

Answer : Rankine’s theory of failure is applicable for brittle materials. Guest’s theory of failure is applicable for ductile materials.  Question 47. What Is The Main Purpose Of A Gear Box In A Vehicle? Answer : To vary the torque at the road vehicles.  Question 48. What Is Endurance Limit? Answer : Endurance limit or fatigue limit is the maximum stress that a member can with stand for an infinite number of load applications without failure when subjected to completely reversed loading.  Question 49. For Tight Leakage Joints, Which Type Of Thread Is Best Suited? Answer : NPT( National Pipe Threads)  Question 50. A Bench Vice Has Which Type Of Thread? Answer : ACME

Material Science Interview Questions  Question 1. What Is The Difference Between The Isotropic And An Isotropic Materials? Answer :

If a material exhibits same mechanical properties regardless of loading direction, it is isotropic. ex:homogeneous cast materials. Materials lacking this property are anisotropic.  Question 2. What Are Orthotropic Materials? Answer : Orthotropic materials are a special class of isotropic materials which can be described by giving their properties in three perpendicular directions ex: wood; composites.  Question 3. A Plain Carbon Steel Has Brinell Hardness Number (bhn) Of 180. What Are The Values Of Rc, Vhn And Ultimate Strength? Answer : Rc = BHN/10 = 18, VHN = BHN = 180 Ultimate strength = 3.48 × BHN MPa = 620 MPa.  Question 4. What Properties Are Needed To Be Considered For Application Calling For Following Requirements? I) Rigidity. Ii) Strength Of No Plastic Deformation Under Static Load. Iii) Strength To Withstand Overload Without Fracture. Answer : i) Reliability – elastic modulus and yield strength. ii) Strength (for no plastic deformation under static loading) – yield point. iii) Strength (overload) – Toughness and impact resistance. iv) Wear resistance – Hardness. v) Reliability and safety – Endurance limit and yield.  Question 5. Explain The Effects Of Alloying Chromium And Nickel In Stainless Steel.? Answer : The addition of nickel and chromium increases the tensile strength and increase in resistance to corrosion takes place.  Question 6. Mention Two Types Of Dislocations?

Answer : Dislocation refers to a break in the continuity of the lattice. In an edge dislocation, one plane of atoms gets squeezed out. In screw dislocation, the lattice atoms move from their regular ideal positions.  Question 7. What Are The Principal Constituents Of Brass? Answer : Principal constituents of brass are copper and zinc.  Question 8. What Is Curie Point? Answer : Curie point is the temperature at which ferromagnetic materials can no longer be magnetized by outside forces.  Question 9. Specific Strength Of Materials Is Very High When They Are In Fibre Size But Lower When They Are In Bar Form - Why? Answer : The crystal structure has ordered, repeating arrangement of atoms. Fibers are liable to maintain this and thus have high specific strength. As for size increases, the condition of ordered and repeating arrangements can’t be guaranteed because of several types of defects and dislocations, and thus the specific strength gets lower.  Question 10. What Is The Percentage Of Carbon In Cast Iron? Answer : 2.5%.  Question 11. Which Element Is Added In Steel To Increase Resistance To Corrosion? Answer : Chromium.  Question 12. Whether Individual Components In Composite Materials Retain Their Characteristics Or Not? Answer : Yes.

 Question 13. Why Is It That The Maximum Value Which The Residual Stress Can Reach Is The Elastic Limit Of The Material? Answer : A stress more than the elastic limit, with no external force to oppose it, we relieve itself by plastic deformation until it reaches the value of the yield stress.  Question 14. Why Fatigue Strength Decreases As Size Of A Part Increases Beyond Around 10mm? Answer : The perfection of material conditions is possible at lower sizes, and as size increases, it is not possible to attain a uniform structure of the material.  Question 15. Distinguish Between Creep And Fatigue? Answer : Creep is low and progressive deformation of a material with time under a constant stress at high-temperature applications. Fatigue is the reduced tendency of material to offer resistance to applied stress under repeated or fluctuating loading condition.  Question 16. While Normal Carburizing And Nit Riding Surface Treatments Increase Fatigue Strength, Excessive Treatment May Decrease The Fatigue Strength. Why? Answer : Normal carburizes/nits riding treatments increases volume due to phase transformation at the surface and introduce residual compressive surface stress and thus increases fatigue strength. By excessive treatment, the high compressive stresses ae introduced but these are balanced by high internal elastic stresses of equal value, and the surface fatigue cracks may develop in the regions of the high tensile stress and lead o early fatigue failure.  Question 17. List At Least Two Factors That Promote The Transition From Ductile To Brittle Fracture? Answer : The manner of loading and the rate of loading promote the transition from ductile to brittle fracture. A machine member may have ductile failure under static loading but may fail in brittle fashion when the load is fluctuating. Similarly a material may evidence ductile failure under tensile loading at ordinary testing speed, but if the load is applied at a high velocity then failure may be brittle.  Question 18. Which Theories Of Failure Are Used For? (a) Ductile Materials (b) Brittle Materials?

Answer : For ductile materials, theories of failure used are maximum shear stress theory and maximum energy of distortion theory; For brittle materials, the theory of maximum principal stress and maximum strain are used.  Question 19. What Is The Common Element Between The Brass And Bronze Metal Alloys? Answer : Copper.  Question 20. What Does The Alloy Designation Fg 250 Indicate? Answer : FG 250 alloy designation indicates Grey cast iron with a tensile strength of 250 MPa.  Question 21. Define Ceramic? Answer : Ceramic is a solid formed by the combination of metallic and non-metallic elements.  Question 22. Give One Example Of Metal Classified As Per Structure As Bcc, Fcc, Hcp And Ccp? Answer : Examples of BCC, FCC, HCP and CCP structures: BCC (Body Centred Cubic) structure – molybdenum; FCC (Face Centred Cubic) structure – Aluminum; HCP (Hexagonal Close Packed) structure – Zinc; CCP (Cubic Close Packing) structure – Copper.  Question 23. What Is The Name Of Solid Solution Of Carbon In Alpha-iron And Delta Iron? Answer : Ferrite and Austenite respectively.  Question 24. Explain The Difference Between Pear Lite And Cementite?

Answer : Pearlite is a eutectoid mixture of ferrite and cementite. Cementide is a chemical compound of iron and carbon.  Question 25. Give One Example Each Of The Following Proportion Of Materials – Dimensional, Physical, Technological And Mechanical? Answer : Roughness, enthalpy, toughness and hardness respectively.  Question 26. For Which Parts The Wahl Factor And Lewis Factor Is Used? Answer : Wahl factor and Lewis factor is used for springs and gears respectively.  Question 27. How Oxygen Gas Can Be Removed From Steel During Melting? What Are Fully Killed Steel? Answer : Oxygen gas can be removed from steel during melting by adding elements such as manganese, silicon or aluminium which, because of their high affinity for oxygen, react with it to form non-metallic oxides such as manganese oxide, silicon oxide and aluminium oxide. Which rise into the slag. Steels in which have has most of their dissolved oxygen removed are called ‘fully killed steels’.  Question 28. Hydrogen Cannot Be Removed Easily From Molten Steel. What Harm Hydrogen Has On Property Of Steel? Answer : Excessive hydrogen in molten steel results in the formation of small fissures often described as hairline cracks or flakes in the steel. Large forgings an alloy steel are particularly sensitive to this phenomenon.  Question 29. What Is Allot Rope? In What Forms Of Cubic Pattern, Iron Exists? Answer : Some elements exist in more than one crystalline form. Each crystalline form is known as ‘allotrope’ of the element. Iron exists in two crystalline forms of cubic pattern, namely, bodycentered cubic (BCC) and face-centered cubic (FCC).  Question 30. When A Material Is Known As Allotropy Or Polytropic? Answer :

A material is known as allotropic aur polytropic if it exists in several forms at a different temperature.

Thermodynamics Interview Questions & Answers  Question 1. State The Third Law Of Thermodynamics. Give Its Limitations And Importance.? Answer : The third law of thermodynamics states that: “The entropy of a perfect crystal of each element and a compound is zero at absolute zero.” Limitations: If any disorder like impurity or imperfection is found in a substance then the entropy of such crystal is non-zero at 0 K. For example: The entropy of pure carbon dioxide and nitric oxide is zero at 0K. This shows that there exists disorder in the arrangement of such molecules. This law is applicable only to pure compounds. Thus we can say that, this law is not applicable to glass which is a supercooled liquid. It is also not applicable to amorphous substance and supercooled solutions. Importance: 1. With the help of this law Thermodynamic properties can be calculated and chemical affinity can be measured. 2. This law helps in explaining the behaviour of solids at very low temperature.  Question 2. Explain The Laws Of Thermodynamics.? Answer : 1. Zeroth law: If any two systems are in thermal equilibrium with the third system, then they are also in thermal equilibrium with each other. 2. First law: First law of thermodynamic states that energy can neither be created nor be destroyed but it can only be converted from one form to another. 3. Second law: This law states that “all processes in nature tend to occur with an increase in entropy and the direction of change always lead to the increase in entropy.” 4. Third law: This law states that “The entropy of a perfect crystal of each element and a compound is zero at absolute zero.”  Question 3. Explain The Following Terms: Isolated System, Open System And Closed System And Give Example Where Ever Possible.?

Answer : 1. Isolated system: A system that can neither exchange matter nor heat with the surrounding is known as an isolated system. For example: Water placed in a vessel that is closed as well as insulated. 2. Open system: A system that can exchange both matter and energy with the surrounding is said to be an open system. For example: A reaction taking place in an open vessel exchanges both energy and matter with the surrounding. 3. Closed system: A system that exchanges only energy and not matter with the surrounding is said to be a closed system. For example: A reaction taking place in a closed metallic vessel.  Question 4. Write A Short Note On Gibbs Free Energy And Derive The Equation For The Same.? Answer : This thermodynamic quantity states that the decrease in value during a process is equal to the useful work done by the system. It is denoted by G and the mathematical equation is: G = H – TS Where, H = heat content T = absolute temperature S = entropy of the system For isothermal process we have G1 = H1 – TS1 for the initial state G2 = H2 – TS2 for final stage Therefore, G2 – G1 = (H2 – H1) – T(S2 – S1) Now, ΔG = G2 – G1 is the change in Gibbs free energy ΔH = H2 – H1 is the change in enthalpy of the system ΔS = S2 – S1 Is the change in entropy of the system Thus the above equation becomes: ΔG = ΔH – TΔS is known as Gibbs-Helmoholtz equation.  Question 5. Why Entropy Decreases With Increase In Temperature?

Answer : ds=dQ/T. Entropy is inversely proportional to the temperature so, as temp. Increases, entropy decreases.  Question 6. Why Different Types Of Sound Are Produced In Different Bikes, Though They Run On Si Engines? Answer : Engine specifications are different in different manufactures like as Bore Diameter (CC), Ignition timing. Also the exhaust passage takes more responsible for sound.  Question 7. How Much Watt Means 1hp? Answer : 746.2 Watt  Question 8. Explain Bicycle Rear Wheel Sprocket Working? Answer : Rear wheel sprocket works under the principle of ratchet and pawl.  Question 9. Definition Of Octane Number And Cetane Number? Answer : Octane No:-Octane number is defined as the percentage, by volume, of iso octane in the mixture of iso octane and h-heptane. It is the measure of rating of SI engine. Cetane No:- Cetane number is defined as the percentage, by volume, of n-cetane in the mixture of n-cetane and alpha methyl naphthalene. It is the measure of rating of CI engine.  Question 10. Which Mechanism Is Used In Automobile Gearing System? Answer : Differential mechanism  Question 11. When Crude Oil Is Heated, Which Hydrocarbon Comes First? Answer : Natural gas (Gasoline)… at 20 Celsius  Question 12. How To Calculate Bearing Number Ti Diameter Of The Inner And Outer?

Answer : Divide the shaft diameter size by 5, it will give last two digit of the bearing no. and according to type of load we have to choose the type of bearing and that will give prior number of the bearing.  Question 13. The Fatigue Life Of A Part Can Be Improved By? Answer : Improving the surface finish by Polishing & providing residual stress by Shot peening.  Question 14. What Happens If Gasoline Is Used In A Diesel Engine, Siesel Engine Will Work? Answer : No, It will not work, as the Compression ratio of Petrol engine is 6 to 10 & that of Diesel engine is 15 to 22. Thus on such high compression, gasoline gets highly compressed & it may blast.  Question 15. Why Poisson Ratio Is Higher In, Rubber/steel/wood? Answer : When a material is compressed in one direction, it usuallytends to expand in the other two directions perpendicular tothe direction of compression. This phenomenon is called the Poisson effect. Poisson’s ratio is a measure of the Poisson effect. For rubber = 0.5 For steel = 0.288 For wood < 0.2 Thus Poisson’s ratio is higher in RUBBER.  Question 16. When A Real Gas Behaves Like Ideal Gas? Answer : A real gas behaves like an ideal gas in low pressure and high temperature conditions.  Question 17. What Is The Significance Of Entropy? Answer : As per the second law of thermodynamics, any heat input to the system (Heat engine) cannot be converted completely into useful work. Some energy is lost and that is called 'unavailable work'. The amount of unavailable work increases as the entropy increases.

 Question 18. What Is The Difference Between Heat Transfer And Thermodynamics? Answer : Heat transfer deals with the energy analysis which in transition and and depends on the modes of heat transfer like conduction, convection and radiation or combination of any modes. Heat transfer deals in non equilibrium domain and conditions while thermodynamics deals with study of system at equilibrium and does not depend on how heat transfer is calculated.  Question 19. At Which Temperature Thermal Radiation Can Become Zero? Answer : Not possible. Because thermal radiation becomes only zero at absolute zero temperature which can never be attained by the third law of thermodynamics.  Question 20. Difference Between Tube And Pipe? Answer : 

 

There always a debate between differentiation of pipe and tube. Pipe is always designated by its Inside Diameter (ID) because main purpose of pipe is to carry fluid, while the Tube is always designated by its Outside Diameter (OD). Pipe's thickness is sometimes called as schedule and tube's thickness is gauge. As per the tolerance basis, tubes requires higher tolerances as to that of pipe and tubes are more costlier in manufacturing compared to pipe production.

 Question 21. Difference Between Flywheel And Governor? Answer : The function of flywheel is to store the energy/power produced during the power stroke of an engine and this stored energy is used during remaining stroke to make piston up and down during working of engine while governor tries control the speed of an engine due to variation in load. It does this work by reducing or increasing the amount of fuel passing to the engine.  Question 22. What Is The Importance Of The Thermodynamics In The Field Of Mechanical Engineering? Answer : All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very important for the mechanical engineers.  Question 23. How Many Laws Of Thermodynamics Are There? Answer :

There are three laws of the thermodynamics. 1. First Law : Energy can be neither created nor destroyed. It can only change forms.In any process in an isolated system, the total energy remains the same. 2. Second Law : When two isolated systems in separate but nearby regions of space, each in thermodynamic equilibrium in itself, but not in equilibrium with each other at first, are at some time allowed to interact, breaking the isolation that separates the two systems, and they exchange matter or energy, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated systems is less than or equal to the entropy of the final exchanging systems. In the process of reaching a new thermodynamic equilibrium, entropy has increased, or at least has not decreased. 3. Third Law : As temperature approaches absolute zero, the entropy of a system approaches a minimum.  Question 24. State Laws Of Conservation Of Energy? Answer : According to the laws of conservation of energy, “energy can neither be created nor be destroyed. It can only be transformed from one form to another.”  Question 25. Is The Boiler A Closed System? Answer : Yes definitely the boiler is a closed system.  Question 26. What Is Carnot Engine? Answer : It was being designed by Carnot and let me tell you that Carnot engine is an imaginary engine which follows the Carnot cycle and provides 100% efficiency.  Question 27. Which Formula Forms A Link Between The Thermodynamics And Electro Chemistry? Answer : Gibbs Helmholtz formula is the formula which forms the link between the thermodynamics and electromagnetism. ∆Hs/R = [∂ lnp /∂ (1/T)]x where: x – mole fraction of CO2 in the liquid phase p – CO2 partial pressure (kPa) T – temperature (K) R – universal gas constant α – mole ratio in the liquid phase (mole CO2 per mole of amine)

 Question 28. Which Is The Hardest Compound Known? Answer : Diamond.  Question 29. What Is Hess Law? Answer : According to the Hess law the energy transfer is simply independent of the path being followed. If the reactant and the product of the whole process are the same then same amount of energy will be dissipated or absorbed.  Question 30. Which Has More Efficiency: Diesel Engine Or Petrol Engines? Answer : Off course Diesel engine has the better efficiency out of two.  Question 31. Explain The Second Law Of Thermodynamics? Answer : The entropy of the universe increases over time and moves towards a maximum value.  Question 32. How Do You Measure Temperature In A Wet Bulb Thermometer? Answer : Wet bulb temperature is measured in a wet bulb thermometer by covering the bulb with a wick and wetting it with water. It corresponds to the dew point temperature and relative humidity.  Question 33. What Is Bending Moment? Answer : When a moment is applied to bend an element, a bending moment exists in the element.  Question 34. What Are The Points In The Stress Strain Curve For Steel? Answer : Proportional limit, elastic limit or yield point, ultimate stress and stress at failure.  Question 35. Define Reynolds Number.? Answer :

Reynolds number is the ratio of inertial force and viscous force. It is a dimensionless number. It determines the type of fluid flow.  Question 36. What Is A Newtonian Fluid? Answer : A Newtonian fluid possesses a linear stress strain relationship curve and it passes through the origin. The fluid properties of a Newtonian fluid do not change when any force acts upon it.  Question 37. How Many Joules Is 1 Btu? Answer : 1 BTU is equal to 1055.056 joules.  Question 38. What Is Ps? Answer : PS is Pferdestarke, the German unit for Horsepower.  Question 39. Explain Otto Cycle? Answer : Otto cycle can be explained by a pressure volume relationship diagram. It shows the functioning cycle of a four stroke engine. The cycle starts with an intake stroke, closing the intake and moving to the compression stroke, starting of combustion, power stroke, heat exchange stroke where heat is rejected and the exhaust stroke. It was designed by Nicolas Otto, a German engineer.  Question 40. Explain The Nomenclature Of A 6203-zz Bearing? Answer : 6 is the type code, which shows it is a single-row ball bearing, 2 is the series, means light, 03 is the bore, which is 17 mm and ZZ is the suffix meaning double shielded bearing.  Question 41. What Is Gear Ratio? Answer : It is the ratio of the number of revolutions of the pinion gear to one revolution of the idler gear.  Question 42. What Is Annealing? Answer :

It is a process of heating a material above the re-crystallization temperature and cooling after a specific time interval. This increases the hardness and strength if the material.  Question 43. Define Torque.? Answer : Torque is defined as a force applied to an object that results in rotational motion.  Question 44. What Is Ductile-brittle Transition Temperature? Answer : It is the temperature below which the tendency of a material to fracture increases rather than forming. Below this temperature the material loses its ductility. It is also called Nil Ductility Temperature

Power Plant Project Interview Questions  Question 1. Name The Four Major Circuits In Steam Power Plant? Answer :    

Coal and ash circuit Air and flue gas circuit Feed water and steam circuit Cooling water circuit

 Question 2. What Consists Of Air And Flue Gas Circuit? Answer : Air and flue gas circuit consists of forced draught fan, air preheater, boiler, furnace, superheater, economizer, dust collector, induced draught fan and chimney.  Question 3. What Consists Of Feed Water And Steam Flow Circuit In Steam Power? Answer : The feed water and steam flow circuit consists of feed pump, economizer boiler drum super heater, turbine and condenser.  Question 4. What Consists Of Cooling Water Circuit And Coal & Ash Circuit In Steam Power Plant?

Answer : The cooling water circuit consists of a pump, condenser and cooling tower. The coal and ash circuit consists of coal delivery, preparation of coal, handling of coal to the boiler furnace, ash handling and ash storage.  Question 5. What Is The Main Purpose Of The Reservoir? Answer : The main purpose of reservoir is to store water received from catchments areas during the rainy seasons and supply the same during the dry season.  Question 6. What Is The Main Purpose Of The Dam? Answer : The main purpose of the dam is to increase the height of water level and also to increase the working head of the hydraulic power plant.  Question 7. Why Trash Rack Is Used? Answer : The trash rack is used to prevent the entry of debris, which might damage the turbine runners and chock up the nozzle of impulse turbine.  Question 8. What Is The Use Of Surge Tank? Answer : The surge tank is used to provide better regulation of water pressure in the system. The surge tank controls the water when the load on the turbine decreases and supplies water when the load on the turbine increases. Thus, surge tank controls the pressure variations resulting from the rapid changes in water flow in penstock and hence prevents water hammer.  Question 9. What Is The Function Of Forebay? Answer : Forebay is considered as naturally provided surge tank. It is temporary water storage when the load on the plant is reduced and provides water for initial increment on increasing load.  Question 10. Explain About Penstock? Answer :

The pipe between surge tank and prime mover is known as penstock. It is designed to withstand high pressure. It is made up of reinforced concrete. In very cold areas, the penstock is buried to prevent ice formation and to reduce the expansion joints.  Question 11. What Is The Use Of Spill Ways? Answer : Spillway is like a safety valve of the dam. It discharges major flood without damaging the dam. It keeps the reservoir level below the maximum level allowed.  Question 12. Write About Prime Movers? Answer : Prime mover converts the kinetic energy of water into mechanical energy to produce electrical energy. Pelton wheel, turbine, Francis turbine, Kaplan turbine and Propeller turbine are prime movers used in hydraulic power plants.  Question 13. What Are The Uses Of Air Filter And Superchargers In Diesel Engine Power Plant? Answer : The purpose of air filter is to filter the air from dust and other suspended particles. The purpose of super charger is to increase the pressure of the engine to increase power of the engine.  Question 14. What Is The Use Of Draft Tube? Answer : The draft tube is used to regain the kinetic energy of water coming out of reaction turbine. It enables the reaction turbine to be placed over tailrace level.  Question 15. What Is The Function Of Cooling System In Diesel Power Plant? Answer : The function of cooling system is to remove heat from the engine cylinder to keep the temperature of the cylinder in low range and extend engine life.  Question 16. What Consists Of Lubrication System In Diesel Engine Power Plant? Answer : The lubrication system consists of oil pumps, oil tanks, filters, coolers and connecting pipes. The purpose of the lubrication is to reduce the friction of moving parts and also pipes to reduce the wear and tear of moving parts.

 Question 17. What Is The Purpose Of Inter Cooler In Gas Turbine Power Plant? Answer : Since the power required compressing the air is less in isothermal process it is required to maintain the, temperature of air constant as far as possible. Hence the air leaving the L.P. compressor is cooled by intercooler and then passed to the H.P compressor.  Question 18. Name Two Combined Power Cycles? Answer :  

Combined cycle of gas turbine and steam power plant. Combined cycle of gas turbine and diesel power plant.

 Question 19. Define Turbo Charging In Combined Gas Turbine And Diesel Cycles? Answer : In the combined cycle, the exhaust gas from the diesel engine is expanded in the turbine, which is coupled with compressor which supplies pressurized air to the diesel engine. This increases diesel engine output. This arrangement is known as turbo charging.  Question 20. What Is The Main Purpose Of High-pressure Boilers? Answer : The high-pressure boilers are used to increase the efficiency of the plant and to reduce the cost of electricity production.  Question 21. State Important Advantages Of High-pressure Boilers? Answer :  

The amount of scale formation is less, since the velocity of water through pipes are more. All parts of the system are heated uniformly, so there is no danger of overheating.

 Question 22. Name Important High Pressure Boilers? Answer :    

La Mont boiler Benson boiler Loeffler boiler Velox boiler.

 Question 23. Write About La Mont Boiler? What Is The Major Disadvantage Of La Mont Boiler?

Answer : La Mont boiler is a forced circulation high pressure water tube boiler. The major disadvantage is the formation of bubbles, salt and sediment on the inner surfaces of the heating surfaces. This reduces the heat flow and steam generation.  Question 24. Write About Benson Boiler? State Some Important Advantages Of Benson Boiler? Answer : Benson boiler is the high pressure, vertical fire tube boiler. This boiler has no drum and is ~designed to operate at critical pressure of 225 bars. Benson boiler has no drum. So the total weight of the Benson boiler is reduced by 20%, when compared to other boilers. The erection of Benson boiler is easier and quicker.  Question 25. Write About Loeffler Boiler? Answer : The major disadvantage in La Mont boiler is the deposition of salt and sediment on the inner surface of the water tubes. It reduces the heat transfer and ultimately the steam generating capacity. In Loeffler boiler, this problem is solved by preventing water from flowing through the boiler tubes. The steam is generated outside the tubes.  Question 26. Explain Reheat Cycle? Answer : If the dryness fraction of steam leaving the turbine is less than 0.88, then, corrosion and erosion of turbine blades occur. To avoid this situation, reheat is used. In the reheat cycle, the expansion of steam takes place in one (or) more turbines. Steam is expanded in the HP turbine first, and then it is reheated. The reheated steam is again expanded in. the LP turbine.  Question 27. What Are The Important Advantages Of Re Heating? Answer :    

Due to reheating, network done increases. Heat supply increases. Thermal efficiency increases. Due to reheating, the turbine exit dryness fraction increases so moisture decreases so blade erosion becomes minimum so life of the turbine will be increased.

 Question 28. Name Different Methods Of Reheating? Answer :   

Gas Reheating. Live stream reheating. Combined gas live steam reheater.

 Question 29. Define Bleeding In Steam Power Plant? Answer : Assume I kg of steam is expanded in the turbine. Before complete amount of steam is expanded, some amount of steam (m kg) is extracted ‘Extracting the steam in the turbine before exhaust is called bleeding. This bled steam is used to heat the feed water.  Question 30. Explain The Term Regeneration? Answer : Regeneration means heating the feed water by steam taken from the turbine. The steam is exhausted (bled) from the turbine at several locations before exhaust and is supplied to regenerative (feed water heater) to heat the feed water.  Question 31. State Some Advantages Of Regeneration Cycle? Answer :   

Heat supplied to boiler becomes reduced. Thermal efficiency is increased since the average temperature of heat addition to the cycle is increased. Due to bleeding in the turbine, erosion of turbine due to moisture is reduced.

 Question 32. Name Different Methods Used To Extract Steam For Heating The Feed Water? Answer :    

Direct contact heater Drain pump method All drains to hot well Cascade system

 Question 33. Define The Term Waste Heat Recovery? Answer :

Waste heat is the heat which is not at all used and exhausted out as a waste product. Waste heat is normally available from the industry in the form of process steam and water at high temperature. Also, the waste heat is discharged with the exhaust gases in so many industries. This heat can be recovered for useful purpose. This process is known as waste heat recovery.  Question 34. What Are The Waste Materials, Which Can Be Used For Fuel For Power Generation? Answer :    

Municipal waste. Industrial waste. Paper waste. Rubber waste.

 Question 35. Write About Waste Heat Boilers? Answer : The waste heat boilers use the waste heat in gases coming out of diesel engines and gas turbines at high temperature (or) use the waste as a fuel in the incineration. Some boilers use the industrial dirty gases for power generation.  Question 36. Write About Fluidized Bed Boilers? Answer : When the high velocity gas is passed through a packed bed of finely divided solid particles, the particles become suspended in the gas stream and the packed bed becomes a fluidized bed. When the gas velocity is very high, the fluidized bed become turbulent and rapid mixing of particles occurs. Ultimately, the, behaviour of mixture solid particles and gas become a fluid. Burning of a fuel in such a state is known as Fluidized Bed Combustion. The boiler plant using this fluidized bed combustion is known as fluidized bed boilers.  Question 37. State Some Advantages Of Fluidized Bed Boilers? Answer : 

  

Any type of fuel solid, liquid (or) gaseous fuel (or) domestic and industrial waste can be used in FBC system. Any type of combustible matter can be burned by adjusting the factors as size, air velocity and rate of feed. High heat transfer rate is possible to the surfaces immersed in the bed, because solid mixing is extremely possible. High combustion efficiency. The solid fuel need not be pulverized in fluidized bed boilers.

 Question 38. Name The Two Types Of Coal Handling?

Answer :  

Out plant handling. In plant handling.

 Question 39. Write About Out Plant Handling? Answer : Out plant handling includes the handling of coal mine to the thermal power plant. These handlings are outside the plant in the following ways.    

Transportation by sea (or) river Transportation by rail Transportation by road Transportation of coal by pipeline.

 Question 40. Write About In Plant Handling Of Coal? Answer : In order to handle large quantity of coal inside the plant, some mechanical handling systems are provided f6r smooth, easy and better controlled operation. The implant coal handling is divided, into following categories.    

Coal unloading Coal preparation Coal transfer Coal storage

 Question 41. Why The Preparation Of Coal Is Necessary? Answer : The coal from coal nines cannot be directly fed into the furnace. Proper preparation of coal should be done before feeding the coal to the furnace. In the coal preparation, the coal passes through the different equipments like 1. Crushers 2. Sizers 3. Dryers and Magnetic Separators.  Question 42. Name The Different Types Of Coal Transforming Equipment? Answer : 1. 2. 3. 4.

Belt conveyors Screw conveyors Bucket elevators Grab bucket elevators

5. Skip hoists 6. Flight conveyors. The coal transfer starts by carrying of coal from unloading point to the storage site.  Question 43. What Is The Use Of Belt Conveyors? Answer : Belt conveyors are mostly used for transporting coal over long distance with large quantity. An endless belt is made to run over a pair of end drums and pulleys and supported by series of roller at regular intervals.  Question 44. Write About Screw Conveyor And Bucket Conveyors? Answer : In screw conveyor, an endless helicoids screw is fitted to the shaft. On one end of the shaft, the driving mechanism is fitted and the other end of the shaft is supported on a ball bearing. While the screw is rotating, the coal is transferred` from one end to the other end. Bucket conveyors are used as vertical lifts. The coal is loaded at the bottom and unloaded at the top in the bucket conveyors.  Question 45. Define Draught, What Is The Use Of Draught In Thermal Power Plants? Answer : Draught is defined as a small pressure difference required between the fuel bed (furnace) and outside air to maintain constant flow of air and to discharge the gases through chimney to the atmosphere. Draught can be obtained by chimney, fan, steam jet (or) air jet (or) combination of these.  Question 46. Write About Classification Of Draught? Answer : Draught is classified as: 1. Natural draught 2. Artificial draught The artificial draught is further classified as:    

Steam jet draught Mechanical draught Induced draught Forced draught

 Question 47. Define The Term Natural Draught And What Are The Advantages Of Natural Draught System? Answer : The tall chimney creates the natural draught by the temperature difference between hot gases in the chimney and cold atmospheric air outside the chimney. The advantages are:    

No external power is required. Air pollution is less since gases are discharged at high level. No maintenance cost. Capital cost is less than artificial draught.

 Question 48. Write About Artificial Draught? Answer : In modem power plants, the draught should be flexible to meet the fluctuating loads and it should be independent of atmospheric conditions. To achieve this, the aid of draft fans becomes must and by employing the draft fans, the height of the chimney would be reduced.  Question 49. Write About Forced Draught System? Answer : In this system, the blower (forced draft fan) is located at the base of the boiler near the grate. Air is forced to the furnace by forced fan and the flue gases are forced to chimney through economizer and air preheater.  Question 50. What Are The Advantages Of Forced Draught System? Answer :   

Since the fan handles cold air, the fan size and the power required are less. No need of water cooled bearings because the air being handled is cold air, Pressure throughout the system is above atmospheric pressure so the air leakage into the furnace is reduced.

 Question 51. How The Induced Draught Is Working? Answer : In an induced draught system, a blower (induced draft fan) is placed near (or) at the base of the chimney. The fan sucks the flue gas from the furnace creating a partial vacuum inside the furnace. Thus atmospheric air is induced to flow through the furnace to aid the combustion of fuel. The flue gases drawn by the fan passes through chimney, to the atmosphere.

 Question 52. Why The Balanced Draught System Is Preferred Than Other System? Answer : In the induced draught system, when the furnace is opened for firing, the cold airs enters the furnace and dilate the combustion. In the forced draught system, when the furnace is opened for firing, the high pressure air will try to blow out suddenly and furnace may stop. Hence the furnace cannot be opened for firing (q) inspection in both, systems. Balanced draught, which is a combination of induced and forced draught, is used to overcome the above stated difficulties.  Question 53. What Is The Difference Between Stocker Firing And Pulverized Fuel Firing? Answer : The stocker firing method is used for firing solid coal where as pulverized firing method is used for firing pulverized coal.  Question 54. What Are The Different Types Of Stockers? Answer : Over feed stockers:  

Travelling grate stockers Spread stockers

Under feed stockers:  

Single retort stocker Multi retort stocker

 Question 55. What Is The Use Of Pulveriser And Name Different Types Of Pulverising Mills? Answer : The pulveriser is used to pulverise the coal in order to increase the surface exposure. Pulverised coal enables rapid combustion. The different types of pulverising mills are: 1. Ball mill 2. Hammer mill 3. Ball and race mill.  Question 56. Name The Two Methods Of Pulverized Fuel Firing System?

Answer :  

Unit (or) direct system. Bin (or) central system.

 Question 57. What Are Advantages Of Unit (or) Direct System Of Pulverized Fuel Firing? Answer : 1. 2. 3. 4.

The layout is simple and economical It gives direct control of combustion Coal transportation system is simple Maintenance cost is less

 Question 58. How The Ash Handling System Is Classified? Answer : 1. 2. 3. 4.

Mechanical handling system Hydraulic system Pneumatic system Steam jet system

 Question 59. Why Ash Handling System Is’ Needed? Answer :   

To remove the ashes from the furnace ash hopper. To transport the ashes from furnace ash hopper to a storage. To dispose the ashes from the storage.

 Question 60. Name Different Types Of Dust Collectors? Answer : 1. Mechanical Dust collector:  

Gravitational separators Bag house dust collector

There are three types of bag house dust collector:   

Open pressure type Closed pressure type Closed suction type

2. Cyclone. Separators 3. Electrostatic Precipitator (ESP)

 Question 61. What Is The Main Purpose Of Chimney? Answer : The main purpose of chimney is to emit the flue gases at a considerable height to avoid nuisance to the surrounding people.  Question 62. What Are The Different Types Of Load Act On The Chimney? Answer : There are two types of loads acting on the chimney namely:  

Its own weight which is considered to as a single vertical force acting through the centroid, and The Wind pressure, which is considered as the horizontal force acting on the centroid of vertical projected area.

 Question 63. Name Different Types Of Chimney? Answer : 1. Steel chimney 2. Site constructed chimney 3. Plastic chimney  Question 64. Define Forced Draft And Induced Draft Cooling Towers? Answer : If the fan is located at the bottom of the tower and air is blown by the fan up through the descending water it is called as forced draft cooling towers. If the fan is located at the top of the tower and airs enters through the louvers located on the tower’s side and drawn up and discharge through the fan casing, it is called as induced draft.  Question 65. What Are The Advantages Of Induced Draft Cooling Tower Over Forced Draft Cooling Tower? Answer : 1. The outlet water comes in contact with the driest air and warmest water comes in contact with most humid air. 2. The re-circulation is seldom a problem. 3. The first cost is low due to the reduction in pump power consumption.  Question 66. What Are The Advantages Of Hyperbolic Natural-draft Cooling Towers?

Answer :    

Since no fans are used power cost and auxiliary equipments cost is reduced. Hyperbolic tower chimney creates its own draft even when there is no wind. Ground fogging and warm air re-circulation are avoided in hyperbolic towers. The structure is more or less self-supported.

 Question 67. What Are The Factors That Affect The Rate Of Evaporation Of Water In Cooling Towers? Answer :     

Amount of water surface area exposed. The time of exposure. The relative velocity of air passing over the droplets. The RH of air. The direction of airflow relative to water.

 Question 68. What Is The Working Principle Of Cooling Towers? Answer : The hot water is sprayed from the top of the tower, while the air is made to flow from the bottom of the tower to the top. This air cools the hot water in the cooling tower. Air evaporates a small percentage of water, there by cooling the remaining water. The air absorbs the heat and leaves at the top of the tower and cooled water leaves at the bottom and recirculated to the condenser.  Question 69. Name Different Types Of Cooling Towers? Answer : The cooling towers are classified as follows. According to the construction of material: 1. 2. 3. 4.

Timber for small tower Ferro concrete for large capacity stations. Multi deck concrete towers for large steam stations Metallic

According to the nature of air draught: 1. Atmospheric (or) Natural draught cooling system 2. Mechanical draught cooling tower.  Question 70. How The Atmospheric (or) Natural Draught Cooling Towers Are Classified?

Answer : In atmospheric (or) natural cooling towers, the natural air provides the required cooling without the use of fans. This is classified into three types: 1. Natural draft spray filled towers. 2. Natural draft packed type towers. 3. Hyperbolic cooling towers.  Question 71. How Mechanical Draft Cooling Towers Are Classified? Answer : Mechanical draft cooling tower is classified into three types: 1. Forced draft tower. 2. Induced draft counterflow tower. 3. Induced draft cross flow tower.  Question 72. How The Dry Type Cooling Towers Are Classified? Answer : The dry type cooling towers are classified into two types ‘as follows: 1. Indirect dry type (or) Heller cooling system 2. Direct dry type-cooling system  Question 73. What Are The Methods To Reduce The Effects Of Particulates? Answer : The effects of particulates can be reduced by the following methods.   

Coal cleaning. Using improved electrostatic precipitator design. Controlling the dust within allowable limit. This can be done by increasing the height of chimney thereby reducing the concentration.

 Question 74. What Are The Equipment Used For Ash Collection? Answer :    

Electrostatic precipitator Fly ash scrubbers Cinder catcher Cyclone dust collector

 Question 75. What Is Meant By ‘desulphurization’ And Name The Methods Adopted For Desulphurization? Answer : Desulphurization of fuel is the process of reducing the sulphur content in the fuel. The following methods are adopted for desulphurization.   

Chemical treatment Forth flotation Magnetic separation

 Question 76. What Are The Methods Adopted To Remove’ S02 Flue Gases? Answer : 1. Wet scrubbing 2. Solid absorbent 3. Catalytic oxidation  Question 77. Write About Co2 Recorders? Answer : In thermal power plants, it is necessary to keep the concentration Of CO2 is low is necessary as possible. To achieve this, a constant recording of concentration Of CO2 These recorders are based on the three different principles, as given below.   

Thermal conductivity cell Chemical absorption cell Density balance

 Question 78. Name Some Of The Automatic Controlling Methods For Feed Water? Answer : 1. 2. 3. 4.

Single element pilot operated system Single element self operated system Two element pilot operated system Three element pilot operated system

 Question 79. What Is The Purpose Of Automatic, Combustion Control? Answer : The main purpose of automatic combustion’ control system is to maintain load against demand, to prevent smoke, to increase boiler house efficiency, to carry out routine adjustments and to provide interlocking safe guards.

 Question 80. What Are The Appliances Known As Boiler Accessories? Answer : The appliances used to increase the efficiency of the boiler are known as boiler accessories. The important boiler accessories are: 1. 2. 3. 4. 5.

Economizer Super heater Air preheater Feed pump Injector

 Question 81. What Are The Methods Adopted To Remove So2 From Due Gases? Answer : 1. Wet scrubbing 2. Solid adsorbent 3. Catalytic oxidation  Question 82. What Is The Necessity Of Automatic Controls For Feed Water? Answer : The electrical load on power plant varies irregular manner. The automatic man control provided at a steam power plant successfully meets over the variable load. The automatic control for feed water is necessary sine the supply of feed water depends upon plant load.  Question 83. What Is The Use Of Air Preheater? Answer : Air pre heater is used to transfer heat from the flue gases to the air before it passes into the furnace for combustion. It is placed between the economizer and chimney. The overall efficiency of the plant may be increased by 10 per cent by the use of air preheater.  Question 84. Write About Boiler Mountings? Answer : The devices used for the efficient operation, proper maintenance, and safe operation boiler mountings. The different boiler mountings are: 1. Water gauge (or) water level indicator 2. Pressure gauge (or) steam gauge

3. 4. 5. 6. 7.

Safety valves Fusible plug Stop valve Blow off cock Feed check valve.

 Question 85. What Is Meant By Boiler Trial? Answer : Steam is generated in boilers under certain conditions of feed water and exists as steam while a certain amount of fuel is burnt. To study the performance of boiler, some experiments are conducted by operating, the boiler for a certain length of time and recording the data. This procedure is known as boiler trial.  Question 86. State The Objective Of Boiler Trial? Answer :  

To determine the thermal efficiency of the boiler when working at a definite pressure. To draw up heat balance sheet for the boiler to check the performance of the boiler.

 Question 87. Define Demand Factor? Answer :   

Demand factor is defined as the ratio of maximum demand to connected load. Connected load is the sum of ratings in kW of equipment installed in the consumer’s premises. Maximum demand is the maximum load, which a consumer uses at any time.

 Question 88. Define Load Curve? Answer : Load curve is a graphical representation between load in kW and time in hours. It. shows variation of load at the power station. The area under the load curve represents the energy generated in a particular period.  Question 89. Define Load Factor? Answer : Load factor is defined as the ratio of average load to the peak load (or) maximum demand.  Question 90. What Includes Fixed Cost? Answer :

Fixed cost includes the following cost. 1. 2. 3. 4. 5. 6. 7. 8.

Cost of land Cost of building Cost of equipment Cost of installation Interest Depreciation cost Insurance Management cost

 Question 91. What Includes Operating Cost? Answer : Operating cost includes the following cost.    

Cost of fuel Cost of operating labour, Cost of maintenance labours and materials. Cost of supplier like

Water for feeding boilers, for condenser and for general use.  

Lubrication oil and, grease. Water treatment chemicals.

 Question 92. What Is The Need Of Depreciation Cost? Answer : Depreciation cost is the amount to be set aside per year from the income of the plant to meet the depreciation caused by the age of service, wear and tear of the machinery and equipments. Depreciation amount collected every year helps in replacing and repairing the equipment.  Question 93. Write About Atomic Number? Answer : The nucleus contains protons and neutrons. The number of protons in a given atom is an atomic number (Z). The atomic number for H is 1 and He is 2.  Question 94. Write About Isotopes Of An Element? Answer : Some elements have the same number of protons in the nucleus but different number of neutrons. As a result, these elements have the same atomic number but different mass number. Such type of elements which ‘have the same atomic number – same number of

protons the same chemical properties but different mass numbers due to different number of neutrons, are known as in the isotopes of an element.  Question 95. What Are The Requirements To Sustain Fission Process? Answer :    

The bombarded neutrons must have sufficient energy to cause fission. The number of neutrons produced must be able to create the rate of fission. The fission process must generate energy. The fission process must be controlled.

 Question 96. Define Multiplication Factor Of A Fission Process? Answer : k =number of neutrons of any one generation/number of neutrons of immediately preceding generation.  Question 97. Define Fertile Materials And Breeding In Reactors? Answer : There are materials like U 235 and Th232 which are not fissile but can be converted into fissile materials by the bombardment of neutrons. Such materials are known as fertile materials. The process of converting more fertile material into fissile material in a reaction is known as breeding.  Question 98. What Are The Desirable Properties Of A Good Moderator? Answer :    

It must be as light as possible It must slow down the neutron as quick as possible. It must have resistance to corrosion. It must have good machinability. It must have good conductivity and high melting point.

 Question 99. What Are The Desirable Properties Of A Coolant? Answer :     

It should not absorb neutron Have high chemical and radiation stability Non-corrosive Have high boiling point Non-toxic

 Question 100. Name Few Types Of Reactors? Answer : Fast reactors, Thermal reactors, natural fuel reactors, Enriched Uranium reactors, water moderated reactors, heavy water moderated reactor, graphite moderated reactor, gas cooled reactors and Sodium cooled reactors.  Question 101. What Are The Advantages Using Co2 As Coolant? Answer :     

Gases do not react chemically with the structural materials. Gas can attain any temperature for a particular pressure. They do not absorb neutron. The leakage of gas will not affect the reactivity. The gas coolant provides best neutron economy.

 Question 102. What Are The Advantages Of Breeder Reactors? Answer :    

It gives high power density than any other reactor. High breeding is possible. High burn-up of fuel is achievable. The operation of the reactor is not limited by Xe poisoning.

 Question 103. What Are The Demerits Of Breeder Reactor? Answer :    

Highly enriched fuel is required Control is difficult and expensive Safety must be provided against melt down Handling of sodium is a major problem

 Question 104. What Are The Advantages Of Sodium In Fast-breeder Reactors? Answer :   

Sodium has very low absorption cross-sectional area. It possess good heat transfer properties at high temperature and low pressure. It does not react with any of the structural materials used in primary circuits.

 Question 105. Name The Different Types Of Mhd Generators? Answer : 

Open cycle MHD

 

Closed cycle MHD Closed cycle MHD with liquid metal

 Question 106. What Is The Working Principle Of Magneto Hydrodynamic Power Plant? Answer : The working principle of MHD is as like that of dynamo. Instead of solid conductor high temperature plasma is passed through the magnetic field at sonic speed. When the gas is passed through magnetic field, current is induced. Electrodes collect this induced current.  Question 107. What Is The Purpose Of Control Rods? Answer : The control rods are used to start the chain reaction, maintain the chain reaction at required level and to shut down the reactor during emergency.  Question 108. What Are The Different Types Of Load Acting On The Chimney? Answer : Its own weight which is considered to act on single vertical force acting through the centroid The wind pressure, which is considered to act on the horizontal force acting on the centroid of vertical projected area.  Question 109. What Is Meant By Nuclear Fission? Answer : Uranium exists in different isotopes of U 238, tP34 and U 235. Out of these, EP35 is most unstable. When unstable heavy nucleus is bombarded with high-energy neutrons, it splits up roughly into two equal fragments and about 2.5 neutrons are released and a large amount of energy is produced. This process is called nuclear fission.  Question 110. Name The Different Components Of Nuclear Reactor? Answer : 1. 2. 3. 4. 5. 6. 7.

Nuclear fuel Moderator Control rods Reflectors Reactor vessel Biological shielding Coolant

 Question 111. State Some Advantages Of Pressurized Water Reactor? Answer :   

The pressurized water reactor is compact In this type, water is used as coolant; moderator and reflector water is cheap and available in plenty) It requires less number of control rods.

 Question 112. What Are The Advantages Of Gas Cooled Reactor Nuclear Power Plant? Answer : 1. Fuel processing is simple. 2. The use of C02 as coolant completely eliminates the possibility of explosion in reactor. 3. No corrosion problem.  Question 113. What Is Breeding In Nuclear Reactor? Answer : The process of producing fissionable material from a fertile material such as uranium 238 (U 238) and thorium 232 (Th 232) by neutron absorption is known as breeding.  Question 114. Name The Coolants Commonly Used For Fast Breeder Reactors? Answer :   

Liquid metal (Na (or) Na K) Helium (He) Carbon dioxide.

Inventory Management Interview Questions  Question 1. Do You Know When Should A Physical Inventory Be Taken? Answer : A inventory should be taken at least once a year. If items are perishable, seasonal or highly demanded a inventory should be taken more often.  Question 2. Explain Can A Computer Help In Forecasting Future Demand? Answer :

Yes, In the market today there are many computer software packages that can compute forecasted demand for goods held in inventory.  Question 3. Do You Know What Does Eoq Stand For? Answer : EOQ stands for Economic Order Quantity.  Question 4. Tell Me Can Forecasting Help In Controlling Inventory? Answer : Yes, through the use of forecasts inventory levels can be set to meet the demands while keeping levels as low as possible.  Question 5. Tell Me What Is Forecasting? Answer : Forecasting is the process of estimating the future demand of a product.  Question 6. What Is Raw Material? Answer : Are those basic inputs that are converted into finished product through the manufacturing process. Raw materials inventories are those units which have been purchased and stored for future productions.  Question 7. Do You Know What Is A Order Point? Answer : A order point is a point in time at which a order is placed to replenish goods in inventory.  Question 8. Do You Know What Is Demand? Answer : Demand is the quantity that customers are willing to buy. Demand can be found through forecasting and is needed to find the EOQ level.  Question 9. Tell Me What Is An Order Quantity? Answer : An order quantity is the amount of goods that an order requests be shipped to the store.

 Question 10. Tell Me What Types Of Forecasting Can I Do? Answer : There are two types of forecasting qualitative and quantitative. Qualitative uses personal opinions to determine forecasts. Quantitative uses numerical data and statistical modeling to determine forecasts.  Question 11. Explain What Is Lead Time? Answer : Lead time is the period of time from which a order for goods is placed until it is received by the store. Lead time is an important consideration for determining when orders should be placed.  Question 12. Suppose I Get A Discount Will It Effect The Eoq Model? Answer : Yes, a discount will cause the basic EOQ model to fail. To use a discount in determine a EOQ you must use the EOQ model with quantity discounts.  Question 13. Tell Me What Is Cycle Count? Answer : A cycle count is an inventory auditing procedure, which falls under inventory management, where a small subset of inventory, in a specific location, is counted on a specified day. Cycle counts contrast with traditional physical inventory in that a full physical inventory may stop operation at a facility while all items are counted at one time. It helps to see the difference between Actual stock and Book Stock. Book Stock is the stock available in the system.  Question 14. Do You Know What Is The Eoq Formula? Answer : The EOQ formula is the square root of 2 times demand times order completion cost divided by carrying cost. The mathematical formula is square root of 2DS/C.  Question 15. Tell Me What Do The Letters In The Eoq And Stocking Cost Formula Stand For? Answer : The letters in the formulas represent the quantity ordered(Q), the carrying cost of a unit(C), the demand for the units(D) and the cost of completing a order(S).

 Question 16. Tell Us What Does Inventory Affect In A Store? Answer : Inventory levels and their values can affect the income of the store, the amount of taxes paid, and the total stocking cost.  Question 17. Tell Me What Skills Make You Great At What You Do As An Inventory Specialist? Answer : I am a stickler for perfection and organization. In addition to this, I possess great leadership qualities which make it easy for me to direct personnel to do their job properly. Possessing knowledge of accounting procedures makes it easy for me to manage related bookkeeping and budget management tasks.  Question 18. Do You Know What Is Interference? Answer : Interference is a factor in forecasting demand. Interference is made up of all the factors that a forecaster has no control over. Factors that may be considered interference include natural disasters, unusual customer demands, or rare events in the business period.  Question 19. Do You Know As An Inventory Specialist, What Are Your Specific Duties? Answer : Working as an inventory specialist, I am required to develop and implement an overall inventory management plan which includes materials procurement, inventory stock levels, and facility needs and personnel management. Additionally, I am required to provide direction to staff members who handle inventory control and make sure any overstocking or shortages are handled in a time efficient manner.  Question 20. Explain Me What Is Opening Stock And Closing Stock? Answer : At the beginning of a reporting period, or after a cycle count, the stock available in your inventory account is the Opening Stock. It is also called as Beginning Inventory. So, there's an Opening Stock. Then, lots of transactions happens - Items are purchased and Sold. And finally Closing Stock is calculated. Closing stock is the amount of inventory that a business still has on hand at the end of a reporting period. This includes raw materials, work-in-process, and finished goods inventory. The amount of closing stock can be ascertained with a physical count of the inventory. It can

also be determined by using a perpetual inventory system and cycle counting to continually adjust inventory records to arrive at ending balances. Closing Stock is an asset. In Inventory Account, it is under debit. In trading Account, it is under credit. Because, it is still not traded.  Question 21. Explain Me When Should Reorders Be Placed? Answer : Times for reordering goods vary dependent on the control system you use and its lead time. In fixed order quantities reorders should be placed when the safety stock is reached. In fixed period systems the reordering is done at set time periods. In just in time systems reordering is based on matching the demand with supply. For just in time a close watch on inventory levels is needed so that reorders are placed before goods are out of stock.  Question 22. Explain Me What If There Is No Savings Or The Models Produce Even Results? Answer : If there is no savings a error in the calculations may have occurred or the model does not fit your case. For instances were the total stocking costs are even you may use either order quantity.  Question 23. Explain Why Is Procurement Considered Such An Important Part Of Inventory Control? Answer : Procurement is the backbone of inventory management. Inventory specialists have to create and maintain liaison with vendors and suppliers, and customers to ensure that supplies are obtained in a timely manner and that there are no shortages when the need arises.  Question 24. Tell Me What Are The Important Considerations In Inventory Control? Answer : For inventory control to work at its best a store must consider the costs of acquisition, carrying, ordering, and stock-out. the store must also look at its reordering system, its budgeting for inventory, insurance and forecasted demand.  Question 25. Explain Me Is The Optimal Order Or Production Frequency Calculated On A Regular Basis As Part Of A Continuous Improvement Process? Answer : Once you've reduced inventories, you'll have to put new processes in place to lower them even more over time. We use an analytical tool that highlights the biggest levers for continually reducing inventory.

For example, instead of working to improve sales forecast accuracy from 70 percent to just 75 percent, establishing a team that's focused on reducing lead times from Asian suppliers may have more impact.  Question 26. Explain What Is Weighted Average Cost? Answer : A weighted inventory average determines the average cost of all inventory items based on the inventory items' individual cost basis and the quantity of each item held in inventory. When a business purchases items for inventory, the business may pay different prices for the inventory items. This price differential can apply to both different inventory items and the same inventory items purchased at different times. The average cost is computed by dividing the total cost of goods available for sale by the total units available for sale. This gives a weighted-average unit cost that is applied to the units in the ending inventory. Weighted Average Unit Cost = Total Cost of Inventory / Total Units in Inventory For Ex: Lets say, we buy item A for 10 AED. We have 10 qty of Item A. Therefore, total cost of Item A is 10 x 10 = 100 AED. In that we sold 3 items. 7 qty left in stock. Total cost of those 7 items = 7 x 10 = 70 AED. After 3 months, item A cost is reduced to 8 AED. And then we bought 10 more for 8 AED. Therefore, total cost = 8 x 10 = 80 AED. Now, we have 7 items bought for 10 AED and 10 items bought for 8 AED. Total 17 items. Therefore total cost = 70 AED + 80 AED = 150 AED. Now, when we calculate the weighted average cost of the 17 items which are to be sold = 150 AED/17 = 8.82 AED.  Question 27. Do You Know Who Decides Key Inventory-related Policy Such As Striking The Right Balance Between Customer Service And Cost-effective Product Inventory Levels? Answer : Many decisions about inventory levels are strategically important. So instead of relying solely on the supply organization to decide, executives need to have a major say in the

fundamental issues that impact inventory management-everything from determining the right breadth and complexity of product offerings to optimal plant and distribution footprints.  Question 28. What Are Finished Goods? Answer : Inventories are those completely manufactured products which are ready for sale. Stocks of raw materials and work-in-process facilitate production, while stock of finished goods is required for smooth marketing operations. Thus, inventories serve as a link between the production and consumption of goods.  Question 29. Tell Us Do You Apply The Above Practices To All Parts Of Your Inventory (finished Goods, Raw Material, Works In Process And Spare Parts) And In All Organizational Entities? Answer : One of the most common mistakes made by supply organizations is looking at only a small subset of all inventory-the finished goods sitting in major warehouses-even though raw materials, works in process, spare parts and even goods in retail stores can make up 50 percent of the total. As a result, they miss potential savings. An organizational map of all inventories will help better prioritize ways to reduce inventories. And all the inventory techniques we've discussed apply.  Question 30. Do You Know What Is Cogs (cost Of Goods Sold) Formula? Answer : For manufacturers, “cost of goods sold” (COGS) is the cost of buying raw materials and manufacturing finished products. For retailers, it's the cost of obtaining or buying the products sold to customers. Opening Stock (Beginning inventory) + Purchases – Closing Stock (End Inventory) = COGS If the company is in a service industry, COGS is the cost of the service it offers. COGS can help companies work out how much they should charge for their products and services, and the level of sales they need to sustain in order to make a profit. The price paid for products is particularly crucial to retailers, as it is often their greatest area of expenditure. But all businesses can benefit from an analysis of COGS, as it can highlight ways of improving efficiency and cutting expenditure.  Question 31. Tell Me Do You Have Regular Visibility Into Excess And Obsolete Stock, And Is It Linked To Targeted Action Plans To Sell Off Or Reduce This Inventory? Answer :

Typically, excess and obsolete stock stems from ineffective sales forecasting, planning or using a business model that fails to factor in product complexity and life cycles correctly. Inventory leaders establish processes to determine why excesses are being created and then develop a plan of action to sell it off. In some instances, the fear of the write-off has led to a large buildup over time of obsolete inventory.  Question 32. Tell Me Are You Able To Break Down Your Operating Inventory Into The Three Major Categories When Reporting Levels-safety, Replenishment And Excess Or Obsolete Stock? Answer : This breakdown makes it easier to make sound decisions about appropriate levels for each of these three areas. It helps determine the minimum safety stock needed to provide an insurance policy against supply chain problems either from manufacturing glitches or distribution uncertainties so that customers get what they ordered. It's useful for pinpointing the amount of inventory required to replenish deliveries every two weeks. And it helps companies find ways to avoid a backlog of excess or obsolete inventory.  Question 33. Explain Me What Should Be Recorded In A Physical Count Of Inventory? Answer : When conducting a physical inventory the classification, location and number in stock of a good should be recorded.  Question 34. Explain Me What Are The Types Of Reordering Systems That Can Be Used In Inventory Control? Answer : There are several types of reordering systems, in this module we discussed three. The fixed order quantity uses fixed quantities of goods ordered at various order points to replenish inventory. The fixed order period use fixed times of reorder with various order quantities to replenish inventory to preset levels. The final system, just in time uses a constant flow of goods to match the level of demand.  Question 35. Do You Know How Is Gr/ir Account Related To Inventory? Answer : If you are involved with inventory, then you need the GR/IR account (Inventory Account) when the IR is posted. If you are not involved about inventory, then the system does not need the GR/IR account when the IR is posted, the system needs a G/L instead of the GR/IR account.

 Question 36. Tell Me How To Determine The Frequency For Ordering And Inventory Production If It's Not Set Solely By Factories Or The Supply Organization? Answer : Ideally, there are two factors: companies should consider calculations that minimize the overall cost such as inventory and changeover costs. They also should base frequency on negotiations between the different parties involved and factor in upcoming events such as promotions and uncertainties like bad weather.  Question 37. Explain Me Do I Need To Recompute Stocking Costs For The Eoq Level? Answer : Yes, in order to compare stock costs when using the EOQ model you must compute the costs for both the original level and the EOQ level of order quantities.  Question 38. Tell Us What Makes A Good Forecasting Model? Answer : A good forecast model will have reasonable costs. the accuracy of its forecasts will allow good decision making. The model will have ample data available for its use and a relevant time span. The model finally will have a low interference level.  Question 39. How To Determine The Numbers To Use In The Eoq Formula? Answer : To determine which numbers to use you must look for the following items. The number of items per order is the quantity(Q). The number of items that can be sold is D. D may be the forecast demand for that particular good. The cost of placing the order is used for S. The final number to find is the carrying cost(C) which is the cost of the item to be held in inventory.  Question 40. Explain How Can The Value Of Inventory Be Determined? Answer : The value can be found using four methods in inventory control. The first is the specific cost in which each item's cost is added together for the inventory's value. A second method is to use the weighted average of the costs for a period to determine value. A third method is first in, first out. In this method value is measured using the latest costs of goods while working towards the beginning of the period until all goods in inventory are valued. The final method is last in, first out. In this method the costs of gods at the beginning of the period are used to determine the inventory's value much like FIFO.  Question 41. Tell Me What Is Shrinkage Calculation In Inventory?

Answer : In financial accounting, the term inventory shrinkage is the loss of products between point of manufacture or purchase from supplier and point of sale. The term shrink relates to the difference in the amount of margin or profit a retailer can obtain. If the amount of shrink is large, then profits go down which results in increased costs to the consumer to meet the needs of the retailer. In retail terms, shrinkage refers to a company's percent loss resulting from damage, product expiration and theft of unsold products. Retail shrinkage can happen anywhere along the production and sale chain, including at the factory, in transit or at the retail location. You can calculate retail shrinkage by dividing the value of goods lost to shrinkage by the total value of goods that are supposed to be in the inventory. Shrinkage = ( Total value of the goods that you are supposed to have in your inventory - Total value of the goods that is physically stocked in your inventory ) / Total value of the goods that you are supposed to have in your inventory. i.e. Shrinkage = (Book stock - Actual Stock) / Book Stock = Total Value of goods lost / Total value of the goods that you are supposed to have in your inventory  Question 42. Explain Me What Is Total Stocking Cost? Answer : Total stocking cost is the cost to the store of holding a good in its inventory. The stocking cost consists of the carrying cost times half the quantity in inventory and the order completion cost times demand divided by the quantity. In its mathematical form the cost is represented by TSC=(Q/2)C + (D/Q)S.  Question 43. What Is Work-in-process? Answer : Inventories are semi-manufactured products. They represent products that need more work before they become finished product for sale.  Question 44. Do You Know What Is The Importance Of Eoq? Answer : The EOQ level is the point at which stocking costs are at their lowest point for a given item.

Materials Management Interview Questions  Question 1. What Is An Order Quantity? Answer : An order quantity is the amount of goods that an order requests be shipped to the store.  Question 2. Explain What Should Be Recorded In A Physical Count Of Inventory? Answer : When conducting a physical inventory the classification, location and number in stock of a good should be recorded.  Question 3. Tell Me Can Forecasting Help In Controlling Inventory? Answer : Yes, through the use of forecasts inventory levels can be set to meet the demands while keeping levels as low as possible.  Question 4. What Are Important Steps In Procurement Life Cycle? Answer : Procurement Process starts with gathering requirements, then creating a purchase requisition and then we create a formal document that has to be sent to vendor i.e. purchase order. After this goods will be supplied by vendor and goods receipt is done along with invoice verification. Then vendor is paid for supplied goods and services.  Question 5. What Is Lead Time? Answer : Lead time is the period of time from which a order for goods is placed until it is received by the store. Lead time is an important consideration for determining when orders should be placed.  Question 6. What Is Demand? Answer : Demand is the quantity that customers are willing to buy. Demand can be found through forecasting and is needed to find the EOQ level.  Question 7. What Types Of Forecasting Can I Do? Answer :

There are two types of forecasting qualitative and quantitative. Qualitative uses personal opinions to determine forecasts. Quantitative uses numerical data and statistical modeling to determine forecasts.  Question 8. What Is Forecasting? Answer : Forecasting is the process of estimating the future demand of a product.  Question 9. What Are Batches And How Are They Searched? Answer : A batch is a collection of similar items from your stock that have the same characteristics. For example, all food items produced on a particular day belong to one batch. Batches are searched using the standard facility (match code, key F4) based on the batch names or other properties that distinguish them from others.  Question 10. What Makes A Good Forecasting Model? Answer : A good forecast model will have reasonable costs. the accuracy of its forecasts will allow good decision making. The model will have ample data available for its use and a relevant time span. The model finally will have a low interference level.  Question 11. What Are The Various Functions /features In Purchasing? Answer : The purchasing view consists of RFQ / Quotation, Purchase Requisition (PR), Purchase Order (PO), Master Data that has several fields like info record, source list, conditions, vendors etc. and finally Outline Agreements.  Question 12. What Is A Rfq And How It Is Different From Quotation? Answer : RFQ is request for quotation and it is a form of invitation that is sent to vendors to submit quotation indicating pricing and their terms and conditions while quotation is a reply by a vendor in response to request for quotation.  Question 13. When Should Reorders Be Placed? Answer :

Times for reordering goods vary dependent on the control system you use and its lead time. In fixed order quantities reorders should be placed when the safety stock is reached. In fixed period systems the reordering is done at set time periods. In just in time systems reordering is based on matching the demand with supply. For just in time a close watch on inventory levels is needed so that reorders are placed before goods are out of stock.  Question 14. What Are Transactions That Will Cause Change In Stock? Answer : Goods receipt and goods issue will cause change in stock as goods receipt will increase warehouse stock and goods issue will decrease warehouse stock.  Question 15. If Inventory Controls Are Followed, What Can I Expect? Answer : By following your inventory policy you should be able to realize important advantages in inventory control. The first is reduced costs for inventories, along with reduced amounts of inventory. Theft and shrinkage should also be reduced if inventory policy is followed. The final benefit will be increased profits for the store.  Question 16. What Is Material Type? Answer : Materials with some common attributes are grouped together and they are assigned to a material type. This will differentiate materials and allow organization to manage different materials in systematic manner in accordance to company's requirement.  Question 17. What Are The Different Kinds Of Special Stocks Available? Answer : Special stocks available are consignment stocks (from vendor), subcontracting stocks (to suncontractor), project stocks, pipeline materials, sales order stocks, stock transfer and third party.  Question 18. Suppose If I Get A Discount Will It Effect The Eoq Model? Answer : Yes, a discount will cause the basic EOQ model to fail. To use a discount in determine a EOQ you must use the EOQ model with quantity discounts.  Question 19. What Is Material And Vendor Data Available At All Organizational Levels? Answer :

Yes, material and vendor data is available at all levels as it is normally created for company and it is valid for the levels below company.  Question 20. Explain How Stock Is Being Transferred From One Plant To Another Plant? Answer : Stock within plants is transferred with the help of stock transport order. One plant order the goods internally from another plant(receiving plant/issuing plant) with the help of stock transport order.  Question 21. What Is Release Procedure? Answer : Release procedure means approval of documents like purchase orders and purchase requisition manually by the criteria defined in the configuration.  Question 22. What Is The Eoq Formula? Answer : The EOQ formula is the square root of 2 times demand times order completion cost divided by carrying cost. The mathematical formula is square root of 2DS/C.  Question 23. When Should A Physical Inventory Be Taken? Answer : A inventory should be taken at least once a year. If items are perishable, seasonal or highly demanded a inventory should be taken more often.  Question 24. What Do You Mean By Consignment Stock? Answer : In Consignment, material is available at our store premises, however it still belongs to the vendor(seller)/Owner of the material. If you utilize the material from consignment stocks, then you have to pay to the vendor.  Question 25. Does The Model Always Work? Answer : No, the model only works for those cases that meet its assumptions.  Question 26. How Do You Create A Pricing Procedure?

Answer : The steps involved in creating a pricing procedure are: 1. 2. 3. 4. 5. 6.

Create condition tables. Create access sequence according to the various condition tables. Create condition types. Assign access sequence to condition type. Create the pricing procedure. List down all the condition types in order so as to suit the business and pricing requirements.

 Question 27. If You Have Multiple Line Items In Purchase Order, Can You Release Line By Line That Purchase Order? Answer : No, release is done only at header level in a combined way for all line items in case of purchase order.  Question 28. What Is The Difference Between A Contract And Scheduling Agreement? Answer : While a scheduling agreement is for consignment, subcontracting and stock transfer, a contract is for Standard items and can be limited to a certain quantity or value. A contract can be created centrally with different pricing conditions for every plant whereas a scheduling agreement needs to be created at that particular plant location. In a contract, only time-dependant conditions can be created whereas in a scheduling agreement, you can have time-dependant or time-independent conditions subject to the customizations in the document type.  Question 29. Can A Computer Help In Forecasting Future Demand? Answer : Yes, In the market today there are many computer software packages that can compute forecasted demand for goods held in inventory.  Question 30. Explain The Importance Of Eoq? Answer : The EOQ level is the point at which stocking costs are at their lowest point for a given item.  Question 31. What Is Source List? Answer :

Source list include list of possible sources of supply for a material over a given framework of time. A particular material can be ordered from different vendors in different time intervals. This information can be maintained in a source list.  Question 32. What Makes Eoq Work For Inventory Control? Answer : The EOQ works if its four assumptions match the case it is used on. The assumptions are: 1. Annual demand, carrying costs and ordering costs can be estimated. 2. Inventory level is divided by 2, no safety stock, goods used uniformly and are gone by next order. 3. Stock-out, customer responsiveness and other costs not considered. 4. No quantity discounts.  Question 33. What Does Eoq Stand For? Answer : EOQ stands for Economic Order Quantity.  Question 34. Explain What Is Invoice Verification? Answer : Once goods are procured from vendor and placed in company's premises through goods receipt then we need to pay to vendor for acquired goods and services. The amount to be paid along with details of material is provided by vendor in form of document that is known as invoice. Before paying to vendor we need to verify the invoice. This process of verifying invoice and paying to vendor is known as invoice verification.  Question 35. Explain What Do You Mean By Reservation? Answer : Sometimes, stock need to be blocked in advance so that it can be available at a particular point of time. This is known as reservation. Reservation ensures that stock is available and it can be used when required. Reserved quantity can be viewed by tcode MMBE.  Question 36. What Is The Importance Of Eoq? Answer : The EOQ level is the point at which stocking costs are at their lowest point for a given item.  Question 37. What Are The Types Of Reordering Systems That Can Be Used In Inventory Control?

Answer : There are several types of reordering systems, in this module we discussed three. The fixed order quantity uses fixed quantities of goods ordered at various order points to replenish inventory. The fixed order period use fixed times of reorder with various order quantities to replenish inventory to preset levels. The final system, just in time uses a constant flow of goods to match the level of demand.  Question 38. Explain What Are Some Of The Movement Types For Stock Transport Order? Answer : One step transfers of materials can be posted using movement type 301. Other movement types are 303, 351, 641, or 643 in the stock transport order.  Question 39. What Is Difference Between Planned And Unplanned Services? Answer : In planned services at the time of procurement specifications like quantity and price are known in advance. It means nature and scope of service is clear before procurement whereas in unplanned services at the time of procurement specifications like quantity and price are not known in advance. It means nature and scope of service is not clear before procurement. These services can be extended as per the requirement.  Question 40. What Do You Mean By Outline Agreement? Answer : Outline agreement is a long term purchasing agreement with vendor containing terms and conditions regarding the material that is supplied by vendor. Outline agreement are valid up to certain period of time and cover a certain predefined quantity or value.  Question 41. What Is Inventory Control? Answer : Inventory control is the process of reducing inventory costs while remaining responsive to customer demands. By this definition a store would want to lower its acquisition, carrying ordering and stock-out costs to their lowest possible levels. However a store would need to have enough inventories to meet any needs of its customers.  Question 42. What Do You Mean By Special Stocks? Answer : Special stocks are stocks that are managed differently as these stocks did not belong to company and these are being kept at some particular location.

 Question 43. What Is Difference Between Contract And Scheduling Agreement? Answer : Contract is a long term outline agreement between vendor and ordering party over predefined material or services over certain framework of time whereas scheduling agreement is a long term outline agreement between vendor and ordering party over a predefined material or service which are procured on predetermined dates over a framework of time.  Question 44. What Is Interference? Answer : Interference is a factor in forecasting demand. Interference is made up of all the factors that a forecaster has no control over. Factors that may be considered interference include natural disasters, unusual customer demands, or rare events in the business period.  Question 45. What Do The Letters In The Eoq And Stocking Cost Formula Stand For? Answer : The letters in the formulas represent the quantity ordered(Q), the carrying cost of a unit(C), the demand for the units(D) and the cost of completing a order(S).  Question 46. How Does The Consignment Cycle Operate? Answer : The various steps in consignment cycle are: 1. 2. 3. 4. 5.

Create consignment info record with proper tax code. Create Purchase order with item category K. Create output condition record for KONS (output type). Authorize Goods Receipt (GR). Payment is settled through MRKO transaction even if invoice verification is not done.

 Question 47. What Is A Gr Blocked Stock And When Is It Used? Answer : The GR blocked stock is an option used in the goods receipt process when you are not sure about the quality of the goods received. In such a case, the stock is maintained as GR blocked either from a material viewpoint or exclusively for a purchase order item.  Question 48. What Is A Order Point? Answer :

A order point is a point in time at which a order is placed to replenish goods in inventory.  Question 49. What Is Mrp? And How Is Lot Size Used? Answer : MRP is short for Materials Requirements Planning and it is a production planning technique that's used to manage the manufacturing process. It is basically used to determine your Material Planning procedure by specifying the various conditions like Reorder Point, Seasonal Requirement, Replenishment, Vendor Managed, Forecast Based and Master Production Scheduling (MPS). Lot size specifies the nature of material requirement in terms of Weekly, Monthly, Quantity and Maximum Replenishment.  Question 50. Can Forecasting Help In Controlling Inventory? Answer : Yes, through the use of forecasts inventory levels can be set to meet the demands while keeping levels as low as possible.

Operations Management Interview Questions  Question 1. Define The Term Operations Management? Answer : Operations management manages the resources needed to produce the company’s products and services. It involves managing people, machines and information.  Question 2. Explain The Decisions Operations Managers Make? Answer : Operations managers must plan the production schedule. This entails deciding how much to produce and in what order. This information would be used to make purchasing and staffing decisions. Operations managers must manage inventory. They must arrange the inventory in the warehouse. They also facilitate the movement of inventory from the warehouse to the retail facilities or the customer.Operations managers also must manage quality levels. This may include inspection of materials, and the use of quality tools such as control charts.  Question 3. Describe The Transformation Process Of A Business. Give Three Examples. What Constitutes The Transformation Process At An Advertising Agency, A Bank, And A Tv Station? Answer :

The transformation process involves taking the various inputs and transforming them into outputs. An advertising agency would transform the time of its staff into an advertising campaign. A bank may use the time of a teller, an input computer, and a bank branch to accept a deposit. A TV station could use the time of its production crew, the video equipment, and the studio to produce a news story.  Question 4. What Are The Three Major Business Functions, And How Are They Related To One Another? Give Specific Examples? Answer : The three major business functions are finance, marketing and operations. Operations entail the production of a product or service and must manage the inputs to production such as workers' time, aluminum, and machine time to create airplane parts Finance manages the assets, such as the building used for production, investments and cash flows related to production, such as providing the needed machines. Marketing generates sales of the product or service, such as finding customers for the proposed airplanes.  Question 5. Identify The Two Major Differences Between Service And Manufacturing Organizations. Find An Example Of A Service And Manufacturing Company And Compare Them? Answer : Manufacturing organizations produce a physical product that can be stored in inventory. Service organizations cannot create an inventory of the service since it is intangible. For example, Ford Motors is a manufacturer. It makes automobiles, customers have little contact with the operation, and they can create an inventory of vehicles. McDonalds is an example of a service organization. Customers go directly to the restaurant where they are served quickly by the staff.  Question 6. What Are The Three Historical Milestones In Operations Management? How Have They Influenced Management? Answer : Three historical milestones are the industrial revolution, total quality management (TQM) and global competition. The industrial revolution changed production processes from a labor focus to a machine focus. TQM caused managers to be more focused on quality and preventing defects. Finally, global competition caused managers to further increase their focus on quality, realizing that to not improve was to “lose the race.”  Question 7. Identify Three Current Trends In Operations Management And Describe Them. How Do You Think They Will Change The Future Of Om? Answer : The lean systems concept is a current trend in operations management. This involves taking a total system approach to creating an efficient operation. This includes concepts such as just-

in-time (JIT), total quality management (TQM), continuous improvement, resource planning, and supply chain management (SCM). Companies are using the Internet to reach out to customers, and suppliers directly. Amazon.com has been able to sell books and many other items directly from its warehouse to people like you and me. The Internet is changing how the supply chains work since we can now eliminate the “middle man” or distributor by selling directly from the factory to the final or end customer. Companies can also ease transactions between businesses, known as B2B commerce, by using electronic trading networks. Large information systems, called Enterprise Resource Planning (ERP) systems, are allowing companies to increase efficiency. These large, sophisticated software programs coordinate, across the entire enterprise, the activities involved in producing and delivering products to customers. Each of these concepts makes intensive use of information and cooperation between partners. OM will most likely continue to be more information intensive and require greater cooperation among all the players in the value chain.  Question 8. Define The Terms Total Quality Management, Just-in-time, And Reengineering. What Do These Terms Have In Common? Answer : Total quality management (TQM) is a philosophy that focuses on meeting the needs of the customer. TQM is not inspection, but actually the prevention of defects. It involves everyone in the organization. Just-in-time is a philosophy that focuses on reducing inventory and other wastes and on the production of the right number of items at the right time. Reengineering focuses on improving business processes in order to improve efficiency. Each of these techniques strives to allow more responsive and more efficient production leading to higher quality and higher customer satisfaction.  Question 9. Describe Today’s Om Environment. How Is It Different From That Of A Few Years Ago? Identify Specific Features That Characterize Today’s Om Environment? Answer : Today’s OM environment is more global, more service oriented, and uses more information technology than that of even a few years ago. Companies can outsource steps of their operation easier. Now even service operations are outsourced off-shore. Information technology allows companies to cooperate more closely, creating tighter supply chains, quicker response and less waste. Specific features include greater outsourcing, greater use of information technology, and deeper cooperation in the supply chain.  Question 10. Is Operations Management Is Important In All Types Of Organization? Answer :

In some types of organization it is relatively easy to visualize the operations function and what it does, even if we have never seen it. For example, most people have seen images of automobile assembly. But what about an advertising agency? We know vaguely what they do – they produce the advertisements that we see in magazines and on television – but what is their operations function? The clue lies in the word ‘produce’. Any business that produces something, whether tangible or not, must use resources to do so, and so must have an operations activity. Also the automobile plant and the advertising agency do have one important element in common: both have a higher objective – to make a profit from producing their products or services. Yet not-for-profit organizations also use their resources to produce services, not to make a profit, but to serve society in some way.  Question 11. What Is Operations Management In The Smaller Organization? Answer : Operations management is just as important in small organizations as it is in large ones. Irrespective of their size, all companies need to produce and deliver their products and services efficiently and effectively. However, in practice, managing operations in a small or medium-size organization has its own set of problems. Large companies may have the resources to dedicate individuals to specialized tasks but smaller companies often cannot, so people may have to do different jobs as the need arises. Such an informal structure can allow the company to respond quickly as opportunities or problems present themselves. But decision making can also become confused as individuals’ roles overlap. Small companies may have exactly the same operations management issues as large ones but they can be more difficult to separate from the mass of other issues in the organization.  Question 12. What Is Operations Management In Not-for-profit Organizations? Answer : Terms such as competitive advantage, markets and business, which are used in this book, are usually associated with companies in the for-profit sector. Yet operations management is also relevant to organizations whose purpose is not primarily to earn profits. Managing the operations in an animal welfare charity, hospital, research organization or government department is essentially the same as in commercial organizations. Operations have to take the same decisions – how to produce products and services, invest in technology, contract out some of their activities, devise performance measures, and improve their operations performance and so on. However, the strategic objectives of not-for-profit organizations may be more complex and involve a mixture of political, economic, social and environmental objectives. Because of this there may be a greater chance of operations decisions being made under conditions of conflicting objectives. So, for example, it is the operations staff in a children’s welfare department who have to face the conflict between the cost of providing extra social workers and the risk of a child not receiving adequate protection. Nevertheless the vast majority of the topics covered in this book have relevance to all types of organization, including non-profit, even if the context is different and some terms may have to be adapted.

 Question 13. What Is The Input–transformation–output Process? Answer : All operations produce products and services by changing inputs into outputs using an ‘inputtransformation-output’ process. Put simply, operations are processes that take in a set of input resources which are used to transform something, or are transformed themselves, into outputs of products and services. And although all operations conform to this general input– transformation–output model, they differ in the nature of their specific inputs and outputs. For example, if you stand far enough away from a hospital or a car plant, they might look very similar, but move closer and clear differences do start to emerge. One is a manufacturing operation producing ‘products’, and the other is a service operation producing ‘services’ that change the physiological or psychological condition of patients.  Question 14. What Is The Processes Hierarchy? Answer : So far we have discussed operations management, and the input–transformation–output model, at the level of ‘the operation’. For example, we have described ‘the whistle factory’, ‘the sandwich shop’, ‘the disaster relief operation’, and so on. But look inside any of these operations. One will see that all operations consist of a collection of processes (though these processes may be called ‘units’ or ‘departments’) interconnecting with each other to form a network. Each process acts as a smaller version of the whole operation of which it forms a part, and transformed resources flow between them. In fact within any operation, the mechanisms that actually transform inputs into outputs are these processes. A process is ‘an arrangement of resources that produce some mixture of products and services’. They are the ‘building blocks’ of all operations, and they form an ‘internal network’ within an operation. Each process is, at the same time, an internal supplier and an internal customer for other processes. This ‘internal customer’ concept provides a model to analyse the internal activities of an operation. It is also a useful reminder that, by treating internal customers with the same degree of care as external customers, the effectiveness of the whole operation can be improved.  Question 15. Operations Management Is Relevant To All Parts Of The Business? Answer : It is not just the operations function that manages processes; all functions manage processes. For example, the marketing function will have processes that produce demand forecasts, processes that produce advertising campaigns and processes that produce marketing plans. These processes in the other functions also need managing using similar principles to those within the operations function. Each function will have its ‘technical’ knowledge. In marketing, this is the expertise in designing and shaping marketing plans; in finance, it is the technical knowledge of financial reporting. Yet each will also have a ‘process management’ role of producing plans, policies, reports and services. The implications of this are very important. Because all managers have some responsibility for managing processes, they are, to some extent, operations managers. They

all should want to give good service to their (often internal) customers, and they all will want to do this efficiently. So, operations management is relevant for all functions, and all managers should have something to learn from the principles, concepts, approaches and techniques of operations management. It also means that we must distinguish between two meanings of ‘operations’:  

‘Operations’ as a function, meaning the part of the organization which produces the products and services for the organization’s external customers; ‘Operations’ as an activity, meaning the management of the processes within any of the organization’s functions.

 Question 16. What Is Mixed High- And Low-visibility Processes? Answer : Some operations have both high- and low-visibility processes within the same operation. In an airport, for example: some activities are totally ‘visible’ to its customers such as information desks answering people’s queries. These staff operate in what is termed a frontoffice environment. Other parts of the airport have little, if any, customer ‘visibility’, such as the baggage handlers. These rarely-seen staff perform the vital but low-contact tasks, in the back-office part of the operation.  Question 17. What Are Implications Of The Four Vs Of Operations Processes? Answer : All four dimensions have implications for the cost of creating the products or services. Put simply, high volume, low variety, low variation and low customer contact all help to keep processing costs down. Conversely, low volume, high variety, high variation and high customer contact generally carry some kind of cost penalty for the operation. This is why the volume dimension is drawn with its ‘low’ end at the left, unlike the other dimensions, to keep all the ‘low cost’ implications on the right. To some extent the position of an operation in the four dimensions is determined by the demand of the market it is serving. However, most operations have some discretion in moving themselves on the dimensions.  Question 18. What Are The Activities Of Operations Management? Answer : Operations managers have some responsibility for all the activities in the organization which contribute to the effective production of products and services. And while the exact nature of the operations function’s responsibilities will, to some extent, depend on the way the organization has chosen to define the boundaries of the function, there are some general classes of activities that apply to all types of operation. 

Understanding the operation’s strategic performance objectives. The first responsibility of any operations management team is to understand what it is trying to achieve. This means understanding how to judge the performance of the operation at

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different levels, from broad and strategic to more operational performance objectives. This is discussed. Developing an operations strategy for the organization. Operations management involves hundreds of minute-by-minute decisions, so it is vital that there is a set of general principles which can guide decision-making towards the organization’s longer-term goals. This is an operations strategy. Designing the operation’s products, services and processes. Design is the activity of determining the physical form, shape and composition of products, services and processes. It is a crucial part of operations managers’ activities. Planning and controlling the operation. Planning and control is the activity of deciding what the operations resources should be doing, then making sure that they really are doing it. various planning and control activities. Improving the performance of the operation. The continuing responsibility of all operations managers is to improve the performance of their operation. The social responsibilities of operations management. It is increasingly recognized by many businesses that operations managers have a set of broad societal responsibilities and concerns beyond their direct activities. The general term for these aspects of business responsibility is ‘corporate social responsibility’ or CSR. It should be of particular interest to operations managers, because their activities can have a direct and significant effect on society.

 Question 19. What Is The Model Of Operations Management? Answer : The first is the input–transformation–output model and the second is the categorization of operations management’s activity areas. The model now shows two interconnected loops of activities. The bottom one more or less corresponds to what is usually seen as operations management, and the top one to what is seen as operations strategy.  Question 20. What Is The Visibility Dimension? Answer : Visibility is a slightly more difficult dimension of operations to envisage. It refers to how much of the operation’s activities its customers experience, or how much the operation is exposed to its customers. Generally, customer-processing operations are more exposed to their customers than material- or information-processing operations. But even customerprocessing operations have some choice as to how visible they wish their operations to be. For example, a retailer could operate as a high-visibility ‘bricks and mortar’, or a lower-visibility web-based operation. In the ‘bricks and mortar’, high-visibility operation, customers will directly experience most of its ‘value-adding’ activities. Customers will have a relatively short waiting tolerance, and may walk out if not served in a reasonable time. Customers’ perceptions, rather than objective criteria, will also be important. If they perceive that a member of the operation’s staff is discourteous to them, they are likely to be dissatisfied (even if the staff member meant no discourtesy), so high-visibility operations require staff with good customer contact skills. Customers could also request goods which

clearly would not be sold in such a shop, but because the customers are actually in the operation they can ask what they like! This is called high received variety. This makes it difficult for high-visibility operations to achieve high productivity of resources, so they tend to be relatively high-cost operations. Conversely, a web-based retailer, while not a pure low-contact operation, has far lower visibility. Behind its web site it can be more ‘factory-like’. The time lag between the order being placed and the items ordered by the customer being retrieved and dispatched does not have to be minutes as in the shop, but can be hours or even days. This allows the tasks of finding the items, packing and dispatching them to be standardized by staff who need few customer contact skills. Also, there can be relatively high staff utilization. The web-based organization can also centralize its operation.

Project Management Interview Questions  Question 1. What Is Project Management? Answer : Project management is a combination of operations such as applying knowledge, skills, tools, techniques in a project followed by the deliverables of the project. As whole project management is managing time, cost and the scope of a project.  Question 2. Who Is A Stakeholder ? Answer : A stakeholder is anyone who has something to gain or lose as a result of the completion or failure of this project or phase.  Question 3. What Is A Project Baselines ? Answer : It defines a logical closure of any deliverable or cycle. Example you have completed the requirement phase with sign off from the client on the requirement document. So you put a baseline and say that further any changes to this document are change request. Versioning of source code is one type of baseline.  Question 4. What Is Effort Variance? Answer : Effort Variance = (Actual effort – Estimated Effort) / Estimated Effort.  Question 5. How Do You Handle Change Request?

Answer : Normally change request are handled by preparing an Impact analysis document and then doing re-estimation.  Question 6. What Is Difference Utp In Testing ? Answer : UTP (Unit Test Plan) are done at smallest unit level or stand alone mode. UTP can be done using NUNIT. Unit testing is done normally by developers.  Question 7. What Is Waterfall Model? Answer : The waterfall model is a sequential software development process, in which progress is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design (validation), Construction, Testing and maintenance.  Question 8. What Is V-model ? Answer : The V-model is a software development process which can be presumed to be the extension of the waterfall model. Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the typical V shape. The V-Model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing.  Question 9. What Is Dual Vee Model? Answer : The Dual Vee Model, like the V-Model is a systems development model designed to simplify the understanding of the complexity associated with developing systems. In systems engineering it is used to define a uniform procedure for product or project development. The model addresses the necessary concurrent development of a system’s architecture with the entities of that architecture and illuminates the necessary interactions and sequences recommended for orderly maturation of a system and systems of systems. This article explains the power of the Dual Vee Model when applied as a reminder model for development of complex systems.  Question 10. Which Institute Offers Pmp Certification? Answer : Project Management Institute (PMI).

 Question 11. What Are The Different Phases Of Sdlc? Answer : SDLC - stands for Software Development Life Cycle. It can be divided in to 7 phases they are: 1. 2. 3. 4. 5. 6. 7.

Preliminary Investigation (Feasibility Study). Requirement Analysis (Analysis). Design of the System. Software Construction. System Testing. System Implementation. System Maintenance.

 Question 12. Explain The Phases Of Software Project? Answer : The different phases of software projects are follows: Initiation: Preparing scope document, requirement documents, Estimation chart, project plan and proposal documents. Planning: Designing test plan and coding standards. Execution: Writing code. Controlling: Testing and establishing change management procedure. Closure: Closing project and move it to maintenance mode.  Question 13. Explain The Popular Software Development Life Cycle Models? Answer : Waterfall model:

This is the oldest model. It represents sequence of stages; output of one stage becomes input of others. Spiral Model: This is improved version of waterfall model. Here we have scope to reiterate and go back to the earlier stages number of times as project progresses. Build and fix model: This is a risky and most unorganized model. In this, developers keep writing code until the customer is happy. Rapid Prototype Model: In this model, we develop prototype which acts like a final product. Once prototype is approved, then the actual development starts. Incremental Model: In this model, the product is divided into sections and each section of the product are created and tested separately.  Question 14. Explain Project Life Cycle? Answer : Waterfall Model: The waterfall model is a software development process which follows a sequential approach. This approach steadily flows downwards like a waterfall which includes the phases of conception, initiation, analysis, design, construction, testing and maintenance. Spiral Model: The spiral model is one of the software development processes which combines the design and prototyping -in -stages together to gain the advantage of top-down and bottom-up approaches. Build and Fix model: This model is one of the worst model for project development. The project is built without specifications and lacks design steps. Essentially, the project is developed, tested, modified as many times as possible. This process continues until the client’s satisfaction is attained. The cost is greater compared to other models. The software engineers are discouraged to use this model. Rapid prototyping Model: To determine and identify the design flaws and obtaining feedback during design process is done by using rapid prototyping model. Product designers and engineers are allowed to view their designs look and function in real world situations by using Rapid Prototyping Model. Incremental Model: The evolution of waterfall model is incremental model. The integration testing, product design and development is done as a series of incremental builds. A popular software evolution model used by many software companies. Incremental model is suitable

and applicable where software requirements are well defined, but their implementation may be delayed; and the basic software functionality are required early.  Question 15. Define Car And Dar? Answer : CAR – Casual analysis and resolution: CAR identifies problem and perform a root cause analysis of the same. CAR needs to be performed at every project phase. Fishbone diagram is one of the ways to perform CAR. DAR- Decision Analysis and Resolution: This is to analyze possible decisions using a formal evaluation process that identifies alternatives against current resources.  Question 16. What Is Dar (decision Analysis And Resolution)? Answer : To analyze possible decisions by using a formal evaluation process which identifies the alternatives against established criteria is done by the DAR. For example a project is to use a third party tools and will not depend on only one tool but evaluate by using three to four tools. In this process certain alternatives are available in case of problems.  Question 17. What Is Car (causal Analysis And Resolution)? Answer : Casual Analysis and Resolution is the process of analyzing    

defects, problems and good practices/positive triggers in a project. Root cause of the same. Identity the respective corrective and preventive actions. Tracking these tasks to closure.

The identification of the root causes scientifically and carrying out their corrective and preventive actions is the advantage of CAR. At the initial stage, all phase and at the end stage of the project, the CAR is needed to be performed on a monthly basis. CAR can be done by using ‘fishbone’ diagram.  Question 18. Define Pareto Principle Or 80/20 Principle? Answer : It is one way of tackling problem in management. It says 20% of the problems lead to other 80% of the problems. According to this principle, we should focus on 20% of the problem. In any software project first 10% and last 10% from the vital part of the project.

 Question 19. What Is Pareto Principle? Answer : Pareto Principle is also known as 80/20 principle. It is a management tool to track problem tracking effectively. This principle says that 20% of the problems lead to 80% of other problems. Hence, in order to concentrating on solving 80% of the problems rather, one can concentrate to solve 20 % of the problems which saves lot of troubles. The analysis and concentration is done for only 20% of the vital problems. In a project the vital problems are the first 10% and the last 10% .  Question 20. Describe Each Levels Of Cmmi? Answer : Maturity level 1 – Initial At this level, there is no proven processes and has no stable environment in the organization. This type of organization frequently exceeds the budget and schedule. Maturity level 2 – Repeatable These organizations have basic processes that are established to track cost and schedule. They have guidelines to repeat the same in the next similar project. Maturity level 3 – Defined In this category, processes are well characterized and understood and are described in standards. Maturity level 4 – Managed These organizations are much more matured than level 3 where processes are only qualitively predictable whereas in level 4 companies, processes are accessed using statistical and other quantitive technique. Maturity level 5 – optimizing These organizations persistently try to improve performance through innovative technological improvement.  Question 21. What Is Cmmi? What Are The Five Levels In Cmmi? Answer : Capability Maturity Model(CMM) is a maturity model of certain business processes in software engineering. The CMM identifies five levels of process maturity for an organization:

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Initial - the starting point for use of a new process. Repeatable – the process is used repeatedly. Defined – the process is defined or confirmed as a standard business process. Managed – process management and measurement takes place. Optimizing – process management includes deliberate process optimization and improvement

 Question 22. What Is Fish Bone Diagram? Or Explain Ishikawa Diagram. Answer :     

Fish Bone Diagram is also called Ishikawa Diagram or Cause and Effect Diagram. It is called Fish Bone Diagram because of its structure. Dr. Kaoru Ishikawa invented it so it is called Ishikawa Diagram. It performs the job of analyzing the causes and their effects pertaining to the Project. So, it is called Cause and Effect Diagram. It helps in identifying the potential causes of problems and finally the root cause which make a difference on the performance of the project. This helps in finding the solutions to the problems which have affected the performance of the last project.

 Question 23. What Is A Fish Bone Diagram ? Answer : Fish bone diagrams are the diagrams that show the causes of a certain events. In designing products, to identify the potential reasons / factors that cause overall effect, the fishbone diagrams are used.  Question 24. What Is Black Box Testing? Answer : Black box testing or functional testing means testing the software for the outputs when specified inputs are provided. It is usually performed to see if the software meets the user’s requirements. There’s no focus on what goes behind running that software. An example of this could be manual testing of the system by a tester, assembly testing.  Question 25. What Is White Box Testing? Answer : White box testing is done to test the accuracy of logic and code of the program. It is done by programmers who know the logical flow of the system. It can be done by testing the classes or components in isolation. One of the ways of doing it is Unit Testing.  Question 26. What Is Black Box Testing And White Box Testing? Answer :

Black box testing is an external perspective of the object that is to be tested to obtain test cases. These tests may be functional or non functional. The valid and invalid inputs are tested by the testers to determine the correct output. Black box testing focuses on functional requirements testing. Also known as glass box testing is used for testing design test cases which are internal in structure. It demands programming skills for identifying the paths through the software. The test inputs are chosen by the tester to exercise paths through the code to determine the outputs that are appropriate.  Question 27. What Is Unit Testing? Answer : Unit testing, also called Component testing is performed by programmers to test that a specified unit of the program meets the expected output when a particular input is provided. Here, the programmer has to know the internal logic and code of the system. It is a way of performing the White box testing. It involves checking that each feature specified in the “Component Design” is implemented in the components. A Unit in unit testing means a module self contained and by itself.  Question 28. What Is Assembly Testing? Answer : Assembly testing moves one step ahead of Unit testing. It checks if two or more modules are able to communicate and produce expected results or not. No Unit in the system can perform stand alone activities. The output of one module may be used as input by another, so it is highly important if the related modules are able to connect and produce the desired result. Assembly testing is a way of Black box testing and can be done through the UI.  Question 29. What Is Regression Testing? Answer : Regression testing is performed to see if the system would work well in case of any enhancements or changes in future. Here, all the scripts are run together to see that others are not affected by a change in one module.  Question 30. What Is System Testing? Answer : System testing is done to see if the system delivers the required features, functional and nonfunctional requirements & outputs. It doesn’t check each component individually but the whole system is checked as one entity. It is done at developers end. The testing for nonfunctional requirements includes: 

Performance Testing.

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Volume Testing. Stress Testing. Documentation Testing. Robustness Testing.

 Question 31. What Is Acceptance Testing? Answer : Acceptance Testing is performed by the client to see if the system delivers what was requested. It looks similar to system testing but the difference is in the focus. Here, the testing is done by Client from his point of view as he is the one who knows the whole process and requirements of his business.  Question 32. What Do You Mean By V-model In Testing? Answer : V-model performs a mapping between the type of test and the stage in project development i.e which test is to be performed at which stage. This has 4 levels of testing the system: 1. 2. 3. 4.

Unit Testing-performed by system team at first level. Integration/ Assembly testing-performed by system team or an independent tester. System Testing- performed by system team. Acceptance testing-performed by the client.

 Question 33. What Is Difference Between Sitp And Utp In Testing? Answer : 

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A test plan that is done at the smallest level or stand alone mode is known as Unit Test Plan. For example, a project is having customer and invoicing modules. So the test on customer module and invoicing module will be done individually. This is Unit Test Plan. Later both customer and invoice is to be tested in one set. To do so, we integrate both into one set and test them. So System Integration Test Plan and Unit Test Plan can be done by using NUNIT. Unit testing is normally done by developers and the system testing is normally done by testing professionals in an integrated mode.

 Question 34. What's The Difference Between Unit Testing, Assembly Testing And Regression Testing? Answer : 

Unit testing ensures that the program unit meets the requirements which are reliable. Unit testing is normally conducted by the programmer who is supervised by the team lead. Testing the individual unit is the main objective of unit testing. Unit testing follows white box testing style.

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Assembly testing demonstrates the interaction among modules in a correct, stable and proper manner which was defined in the functional requirements that are provided by the client. Assembly testing follows black box testing style. Regression testing ensures the proper functionality of an application irrespective of changes or enhancements to the system. The testers will run all the scripts in order to ensure that nothing has been affected.

 Question 35. What Is V Model In Testing? Answer : The mapping of the type of testing to the stage of development in a given project is done by V model. In this model of testing there is a testing stage for every development stage which means a mapping between the development and a testing.  Question 36. Who Forms The Part Of Six Sigma Implementation Team? Answer : Attaining Six Sigma is a team effort. An organization who wants to attain Six Sigma needs a lot of restructuring and change in attitude. It includes building up the following roles to take up the required responsibilities: 1. Executive Leadership-Includes CEO and other top management team members. They set up the vision of Six Sigma and empower their team mates with the freedom and resources required for the improvements in the process. 2. Champions- Responsible for the implementation of the process in an integrated manner throughout the organization. They come from Top management. 3. Master Black Belts-Act as in-house expert coach for the organization. They assist Champions and train Black Belts and Green Belts. 4. Black Belts-Apply Six Sigma methodology to specific projects. Their focus is on execution of activities for Six Sigma. 5. Green Belts-These are like the soldiers on the war front who actually implement the planned action.  Question 37. What Is Six Sigma? Answer : SIX sigma is one of the business management strategies. Six Sigma is used to improve quality of process outputs which identifies and removes the causes of defects and variations in manufacturing and business processes. It implements a set of management methods and creates a special infrastructure of people within the organization who are the experts in these methods. A well defined sequence of steps is followed by each six sigma project and has quantified financial targets.  Question 38. What Are Function Points? Answer :

FPA is a process to break system into discrete pieces and analyze them. Software application is a combination of elementary process. FPA is the way to identify elementary processes and analyze them. There are two types of elementary process: 

dynamic and static elementary process.

 Question 39. What Are The Different Elements In Functions Points? Answer : The elements in functions points are:   

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External Inputs: It is an elementary process which allows the data to cross the boundary from outside to inside. External Outputs: A elementary process which allows the data passes across the boundary from inside to outside External Inquiry: It is an elementary process which has both input and output components which results data retrieval from one or more internal logical files and external interface files. Internal Logical Files: An identifiable group of logically related data that resides entirely within the applications boundary and is maintained through external inputs. External Interface Files: An identifiable group of logically related data that is used only for reference purpose. The data is completely persisted outside the application and is maintained by another application.

 Question 40. What Is Project? Answer : 1. A Project is a temporary endeavor to provide unique product or service. 2. Project is a temporary effort of work, a one-time event that meets the following criteria:   

Has a start and an end date. Has schedule, cost, and quality constraints. Is a unique endeavor and contains risk.

 Question 41. What Is Project Plan? Answer :  

The project plan is the fundamental document directing all activities in pursuit of the desired objective. The plan may change as time passes, but nevertheless, it represents the project manager's continuing view on what needs to be done by whom and when.

 Question 42. What Is A Project Management?

Answer :   



It defines project management as "the application of knowledge, skills, tools, and techniques to project activities to meet project requirements." In the project management triangle we are concerned with the management of the project's time, cost, and scope. These concerns lead us to manage the project's quality, risk, communications, integration, schedule, performance, stakeholder needs, desires, requirements, and expectations. The project management processes—initiation, planning, execution, control, and closeout—take place in each of the project phases, and the phases of the project must use all of the project management processes.

 Question 43. What Makes A Good Project Manager? Answer : A Project Manager is active doer, not bystander.  Question 44. What Is Triple Constraint Triangle In Project Management? Answer : It is the balance of the project’s scope, schedule and cost. It is also called as Dempster’s triangle.  Question 45. What Is A Fish Bone Diagram? Answer : Fishbone diagrams also called as Ishikawa diagrams (or cause-and-effect diagrams) show the reasons behind a certain event. In project management, this tool is used in Quality Management & Risk Management processes.  Question 46. What Is 80/20 Principle? Answer :  

80/20 principle is also called as Pareto's principle. It believes that 20% os tasks consume 80% energy for e.g. - 20% tasks in development consume 80% time, 20% of project personnel perform 80% task etc.

 Question 47. Differentiate Between Sitp And Utp In Testing? Answer :  

SITP - System Integration Test Plan - This test is performed in an integrated mode usually by the testing team. UTP - Unit Test Plan - This test plan is performed at the smallest level or in a standalone mode. It is usually performed by the developers.

 Question 48. What Is Cmmi? Answer :  

CMMI stands for Capability Maturity Model Integration. It is a process improvement approach that provides organizations with the essential elements for effective process improvement.

 Question 49. What Are The Five Levels In Cmmi? Answer : In case of development CMMI ratings are awarded from 2 to 5.    

Level 2 - Managed Level 3 - Defined Level 4 - Quantitatively Managed Level 5- Optimizing

 Question 50. What Is Dmaic And Dmadv? Answer :  

DMAIC is a series of steps used to measure defects in business processes and improve profitability. The five steps are: Define, Measure, Analyze, Improve, and Control. DMADV - This is also a series of steps to measure and analyze the defects and produce better. The steps here are: Define, Measure, Analyze, Design, and Verify.

 Question 51. What Is Mpmm? Answer : MPMM is a Project Management Methodology which provides a complete "framework" for managing projects. This framework provides you with a step-by-step walkthrough of the phases, activities and tasks to be undertaken to complete a project. By following the Project Life Cycle framework for your project, you will greatly enhance your chances of project success.  Question 52. As A Project Manager How To Add Value To Your Project? Answer : Project Manager Add Value By:      

Define Proper Communication Plan. Maintain Clear Functional and Technical Documentation. Arrange Brainstorming session within the team to deliver best quality of services. Improve Technical competency in team through different approach. Maintain Team Morale with Creative and fun activities. appropriate resource backup and risk plan.

 Question 53. What Motivates You? Answer : A little appreciation for a successfully completed work. If failed in that task, I am motivated to do it better than ever. If completed successfully, the success motivates me to go in for a tougher project/work which is a new challenge for me. As it is, winning challenges is the spirit in me. 1. When I am able to make significant positive contribution in a challenging situation, thereby helping in the overall success of the Task / Project. 2. When organization shows confidence in me by choosing me amongst many for a tough and challenging assignment.  Question 54. What Are The Functions Of Project Management Tool? Answer : Following are some functions of Project Management tool:       

Task management. File storage. Reporting functions. Commenting and message boards. Client access. Subcontractor task assignment. Time tracking.

 Question 55. What Is Project Planning? Answer : Project Planning defines in detail the project activities and the product that will be produced, and describes how the project activities will be accomplished. Project Planning defines all major tasks, estimates the time and resources necessary to complete them, and provides a framework for management review and control. Project Planning activities include defining and documenting the following:     

Work to be performed, Project goals, Estimates for planning, tracking, executing, and controlling the project, Commitments of the affected groups, and, Project alternatives, assumptions, and constraints.

 Question 56. What Are The Different Project Management Tools? Answer :

The different Project Management tools are MS Project, Templates, eBooks, flowcharts Compliant with PMBOK 4th Edition, EPOs (Electronic Project Offices) etc.  Question 57. What Do You Mean By Business Object? Answer : Business Object is a new query and report software program. It is a part of CSC software package. It is capable of performing more sophisticated mathematical calculations than IQ objects.  Question 58. What Do You Mean By Condition Object? Answer : Condition Object is a mode, state, situation and a condition which imposes upon an object without which knowledge and thought are alleged to be impossible.  Question 59. What Do You Mean By Customizing Object? Answer : A Customizing object in a SAP component is an object which is customized with the same contents in another component. The contents of the customizing objects have to be corresponding in different systems in a system landscape.  Question 60. What Is A Triple Constraint Triangle In Project Management? Answer : Project cost, schedule and scope are depicted as a project management triangle. The triangle is formed by customer as the center point and the three aspects form the sides of triangle. In order to gain customer satisfaction, the project management team should deliver scope in propose schedule and cost. In case any leg is gets disturbed, the other two legs gets affected. For example, if the customer increases the scope, then the other two legs-schedule and costget affected a lot.  Question 61. Who Is Stakeholder ? Answer : Project stakeholders are individuals and organizations that are actively involved in the project, or whose interests may be affected as a result of project execution or project completion. They may also exert influence over the project’s objectives and outcomes. The project management team must identify the stakeholders, determine their requirements and expectations, and, to the extent possible, manage their influence in relation to the requirements to ensure a successful project.  Question 62. What Is The Purpose Of Project Management?

Answer : To provide management with valid, auditable status on which to base management decisions.  Question 63. Why Should The Project Be Planned? Answer : The main reason for planning a project is for cost expediency. Proper project planning will insure that the amount of work to be accomplished, the time allotted to satisfactory complete the work scope, and the resources required to complete the work scope are equally balanced. Every project undergoes some amount of change while in progress. Proper planning allows for the assessment of the impact of change prior to implementing the change.  Question 64. What Is The Most Important Safe Guard Provided By Project Planning? Answer : Proper planning includes the documentation of the work scope in language that is understandable by the individuals who must accomplish the work scope. This single step when properly accomplished will save many false starts as well as preventing the waste of resources working on efforts which are not required to obtain the desired goals of the project.  Question 65. Why Should A Company Have A Project Management System? Answer : The customer may wish to know how the company manages a project. The customer wants some assurance that the company can deliver the project on time and within budget. Senior management wants a valid insight on how the project is progressing. History is required of past performance so that new proposals can be created based on fact. The company desires to be a superior performer when compared to the competition.  Question 66. Does Each Project Have To Create Its Own Management System? Answer : The style of the individual project manager will normally vary for each project. It is the responsibility of senior management to put in place a policy and procedure, supported by a selection of project management tools and formats, which will assure that the status reporting is readable, auditable, and valid.  Question 67. What Are The Tools Needed For A Project Management System? Answer : A work definition policy and format, a scheduling procedure, a resource budgeting methodology and format, a real time data collection/reporting system, a material control and

accountability subsystem, a change control subsystem, and a monthly formal status review format to be used by senior management.  Question 68. What Should The Project Manager Look For In A Scheduling System? Answer : The three basic elements that the project scheduling systems should provide are; a common basis for communication at all operational levels of the project, a basis for regular status reporting, the use of the management by exception technique.  Question 69. What Is A Work Breakdown Structure (wbs)? Answer : The work breakdown structure defines the total project. A work breakdown structure is a product oriented, family tree composed of hardware elements, software elements, and service elements. The work breakdown structure relates project elements or work scope definitions to each other and to the end product. The work breakdown structure is not an organization chart of company personnel.  Question 70. What Is A Project? Answer : A project is synthesizing predetermined amounts of the resources of an organization to generate something that will assist an organization in designing an executing its strategies.  Question 71. What Is Critical Path? Answer : Critical Path is the longest path from the beginning event to the end event. The minimum time required for completing the project is the duration on the critical path.  Question 72. What Is A Gantt Chart? Answer : A Gantt Chart is a way of illustrating multiple, time-based activities on a horizontal time-line.  Question 73. What Is The Difference Between A Risk And An Issue In The Context Of Project Management? Answer : An issue is a problem or concern that may impede the progress of the project if not addressed. A risk is any factor (or threat) that may adversely affect the successful completion of the

project in terms of achievement of its outcomes, delivery of its outputs or adverse effects upon resourcing, time, cost and quality.  Question 74. When Is A Project Risk No Longer A Risk? Answer : A risk is no longer a risk when it no longer is a factor (or threat) that may adversely affect the successful completion of the project. This is usually as a result of mitigation strategies taken, if the threat has been realized, or if there has been a change in the environment that makes the risk no longer relevant.  Question 75. Is It Still Worthwhile To Do Risk Management When A Project Is Half Over? Answer : Yes, there are still risks associated with a project even if it is half over. This also forms a baseline for the remainder of the project.  Question 76. What Are The Benefits Of Risk Management In The Context Of Project Management? Answer : The benefit of risk management is to increase the likelihood that the project will be completed successfully by ensuring levels of risk and uncertainty in the project is properly managed. It enables those involved to identify possible risks, the manner in which they can be contained and the likely cost of mitigation strategies.  Question 77. How To Identify Project Risks? Answer : Risk identification in the Project Management is often done by using brainstorming sessions to identify and clarify the main risks that may work against the project achieving its stated outcomes. It is important to clearly define the scope of the project so that the identification of risks can remain focused upon what potentially threatens the achievement of outcomes, delivery of outputs, level of resourcing, time, cost and quality.  Question 78. What Is A Risk In The Context Of Project Management? Answer : In the context of Project Management, a risk is any factor (or threat) that may adversely affect the successful completion of the project in terms of achievement of its outcomes, delivery of its outputs or adverse effects upon resourcing, time, cost and quality.

Project Manager Interview Questions  Question 1. What Is A Process? Answer : It is a set of structured and related activities which are performed to achieve a specific business goal. They can be categorized into 3 sub categories:   

Management processes Operational processes Supporting processes

 Question 2. What Is Software Project Planning? Answer : It is a set of activities that are collectively called project planning. In project planning a software company considers the following points:      

Scope of the project. Feasibility analysis. Deadline of the project. Estimation of resource cost and schedule. Risk analysis. Overall Budget.

 Question 3. What Is The Meaning Of Scope Of The Project? Answer : The functions and features that are to be delivered to the customer is called the scope of the project. Performance, user interface design, and constraints should meet the customer requirement. Software scope is can be developed after communication with all members those are directly or indirectly involved in the project.  Question 4. What Are The Different Project Scheduling Techniques? Answer : Program evaluation and review technique (PERT) and the critical path method (CPM) are two project scheduling methods that can be applied to software development. CPM provides critical path to analyze project and duration. PERT uses

TE = (O + 4M + P) / 6 formula for the expected completion time. Where O=optimistic time P=pessimistic time M=most likely time TE =expected time Describe the risk in software engineering. Risk is a potential problem, it may come or it may not come while developing the software. Risks are uncertain. It is a good idea to analysis the risk, what is the chance to occur the risk, what will be the impact on the project and what are the positive planes to overcome of these risks is. There are two types of risk strategies: Reactive risk strategies and proactive risk strategies. In reactive risk strategies software team come in action when something goes wrong. A proactive risk strategy starts with long before technical work is initiated. Potential risks are identified and their impacts are analyzed. Then, the software team establishes a plan for managing risk.  Question 5. What Are The Different Types Of Software Risks? Answer : The different types of risks are as follows: Project risks: This type of risk can destroy your project plan. The release date of project may postpone further and cost will increase. Technical risks: Due to technical risk implementation may become difficult or impossible. Technical risks identify different types of problem such as design, implementation, interface, verification, and maintenance problems. Business risks: There are different types of business risk such as market risk, strategic risk, sales risk, management risk, budget risk.  Question 6. What Are The Different Software Reengineering Activities? Answer : Different software activities are as follows: Inventory analysis: The inventory is nothing but a type of spreadsheet model that contain detailed description of every active application. It should be updated in regular time period. Document restructuring: Legacy system can have poor documentation or there is no documentation. Organization prepared documentation for better understand of system but is very time consuming.

Reverse engineering: It is used to extract design information from source code. We can understand the system by using reverse engineering. Code restructuring: In legacy system some module have very poor coding pattern so it is very difficult to understand, test and maintain. In such cases, those module have coding problem, can be restructured. Data restructuring: When data structure is weak, the data are reengineered. A program with weak data structure will be difficult to accept and enhance. Forward engineering: Forward engineering is used to recovers design information from existing software and uses this information to change the existing system. It will improve the overall quality of the system.  Question 7. Describe Capability Maturity Model (cmm)? Answer : Every organization has some process to develop the software. Software Engineering Institute (SEI) has developed a model that provides the different levels of process maturity. In this model, in every level there are some key activities required at different levels of process maturity. There are five level of capability maturity model (CMM): 1. 2. 3. 4. 5.

Level 1: Initial. Level 2: Repeatable. Level 3: Defined. Level 4: Managed. Level 5: Optimizing.

 Question 8. How Does A Project Manager Can Avoid The Above Given Ten Points For The Success Of Project? Answer : Reel suggests these five-part commonsense approaches to software projects:     

Start on the right foot. Maintain momentum. Track progress. Make smart decisions. Conduct a postmortem analysis.

 Question 9. Describe The 4 P’s In Software Project Management? Answer :

Software project management focuses on the four P’s: people, product, process, and project. The People: For success of any type of project, the most important factor is the skilled people. These people participated actively for the success of project. Software Engineering Institute has developed a people management capability maturity model (PM-CMM), that guides the organization for improve the capability of people and how to tackle complex applications. The people management maturity model focus on the following key practice areas for software people: recruiting, selection, performance management, training, compensation, career development, organization and work design development. An organization that follows PM-CMM in the people management area has a higher success rate of software. The Product: Before developing any software product objectives and scope should be properly defined. The software analyst and customer must meet to define product objectives and scope. The Process: There are different types of model available that are used to develop the software.       

Linear sequential model Prototyping model RAD model Incremental model Spiral model WINWIN spiral model Component-based development model.

We can choose any model according to the need of software development and need of customer. The Project: For the success of any project we must understand the risk/problem that may or may not come in future. According to John Reel the following ten points indicate that an information systems project is in trouble: 1. Software people don’t understand their customer’s needs. 2. The product scope is poorly defined. 3. Changes are managed poorly. 4. The chosen technology changes. 5. Business needs change or are ill-defined. 6. Deadlines are unrealistic. 7. Users are resistant. 8. Sponsorship is lost or was never properly obtained. 9. The project team lacks people with appropriate skills. 10. Managers [and practitioners]

 Question 10. What Are The Csfs In The Software Project Management ? Answer : The CSFs (critical success factors) for a successful software project management are listed blow:    

 

Change management is very essential. Leadership & motivating employees for giving direction. Team Orientation is crucial. Cultural & ethnic diversity is also needed for maintaing a cordial environment.As different companies around the world is having the EEo(equal employability opportunity) foe their employees. The cost evaluation must be done diligently in the given time frame. Lucidity in communication is very essential.

Field Instrumentation Interview Questions  Question 1. What Are Different Types Of Orifice Plates? State Their Uses? Answer : Different orifice plates are: 1. Concentric 2. Segmental 3. Eccentric Concentric: These plates are used for ideal liquid as well as gases and steam service. Concentric holes are present in these plates, thats why it is known as concentric orifice. Segmental: This plate has hole in the form of segment of the circle. This plate is used for colloidal and sherry flow measurement. Eccentric: This plate has the eccentric holes. This plate is used in viscous and sherry flow measurement.  Question 2. How Do You Identify An Orifice In The Pipeline? Answer : An orifice tab is welded on the orifice plate which extends out of the line giving an indication of the orifice plate.  Question 3. Why Is The Orifice Tab Provided? Answer :

Following reasons justify for providing orifice tab: 1. 2. 3. 4. 5.

Indication of orifice plate in a line The orifice diameter is marked on it. The material of the orifice plate. The tag number of the orifice plate. To mark the inlet of an orifice.

 Question 4. Explain Bernoulli’s Theorem. State Its Application? Answer : Bernoulli’s theorem states that the ‘total energy of a liquid flowing from one point to another remains constant’. It is applicable for non-compressible liquids. For different types of liquid flow Bernoulli’s equation changes. There is direct proportion between speed of fluid and its dynamic pressure and its kinetic energy. It can be used in various real life situations like measuring pressure on aircraft wing and calibrating the airspeed indicator. It can also be used to low pressure in the venturi tubes present in carburetor.  Question 5. How Can A D.p. Transmitter Be Calibrated? Answer : D.P. transmitter can be calibrated using following steps: 1. Adjust zero of Transmitter. 2. Perform static pressure test: Give equal pressure on both sides of transmitter. Zero should not shift either side. If the zero shifts then carry out static alignment. 3. Perform vacuum test: Apply equal vacuum to both the sides. Zero should not shift. 4. Calibration procedure: Give 20 psi air supply to the transmitter and vent L.P. side to atmosphere. Connect output of the instrument to the standard test gauge. Adjust zero. Apply required pressure to the high pressure side and adjust the span. Adjust zero gain if necessary.  Question 6. How Is Flow Measured In Square Root? Answer : Flow varies directly as the square root of pressure. Thus, F=K of square root of applied pressure. Since this flow varies as the square root of differential pressure. The pressure pen does not directly indicate flow. Thus flow can be determined by taking the square root of the pen. Assume the pen reads 50% of the chart. So, flow can be calculated using the pen measure in the chart.  Question 7. Name Different Parts Of A Pressure Gauge. Explain The Use Of Hair Spring In The Pressure Gauge? Answer : Pressure gauge includes following components:

1. 2. 3. 4. 5. 6. 7.

‘C’ type bourdon tube. Connecting link Sector gear Pinion Gear Hair spring Pointer Dial

Use of hair spring: Hair spring is responsible for controlling torque. It is also used to eliminate any play into linkages..  Question 8. How D.p. Transmitter Can Be Applied To Close Tank? Answer : In closed tank, bottom of the tank is connected to the high pressure side of the transmitter. Top of tank is connected to the lower pressure side of the transmitter. In this way vessel pressure can be measured.  Question 9. How D.p. Transmitter Can Be Applied To Open Tank? Answer : In open tank the lower pressure side is vented to the atmosphere. All pressure is applied to the high pressure side. This vessel pressure is measured through high pressure side.  Question 10. Explain The Working Of An Electronic Level Troll? Answer : The variation in level of buoyancy resulting from a change in liquid level varies the net weight of the displacer increasing or decreasing the load on the torque arm. This change is directly proportional to change in level and specific gravity of the liquid. The resulting torque tube movement varies the angular motion of the rotor in RVDT providing a rotor change proportional to the rotor displacement, which is converted and amplified to a D.C. current.  Question 11. Explain The Working Of An Enraf Level Gauge? Answer : Enraf level gauge is based on the ser powered null balance technique. A displacer serves as continuous level sensing element. A two phase ser motor controlled by a capacitive balance system winds unwinds the the measuring wire until the tension in the weight springs is in balance with the weight of the displaced part immersed in the liquid. The sensing system in balance measures the two capacitance formed by the moving central sensing rod provided by the two capacitor plates and the si plates.  Question 12. What Is The Constant Voltage Unit? Answer :

The constant voltage circuit consists of a rectifier, CR and a filter capacitor. It is followed by two stages of zener regulation. Abridge configuration is provided to lamp line voltage zener regulation. Regulation 1 and regulation 2 provides relatively provide constant current. Resistors form a bridge that may remoment line voltage effects.  Question 13. Explain The Burnout Feature? Answer : Burnout provides the warnsug feature of driving indicator at the end of scale, if the input circuit is open. A burnout resistor is provided which develops a voltage drop between the measuring circuit and amplifier. The polarity of the signal determines the direction of the servo drive upon an open circuit in the input. Upscale burnout: R value 10 M Downscale burnout: R value 22 M  Question 14. Why Thermowells Are Used? What Materials Are Used In Thermo Wells? Answer : In numerous applications, it is neither desirable nor practical to expose a temperature sensor directly to a material. Wells are therefore used to protect against damage corrosion, arosion, aborsion and high pressure processes. A thermowell is also useful in protecting a sensor from physical damage during handling and normal operations. Materials used in thermowells: Stainless steel, Inconel, Monel, Alloy Steel, Hastelloy  Question 15. How Is Automatic Reference Junction Compensation Carried Out In Temperature Recorders? Answer : In automatic reference junction compensation, variable nickel resistor is used. As the temperature changes, so does its resistance. This reference junction compensator is located, so that it will be at the temperature of the reference junction. The reference junction is at the poset where the dissimilar wire of the thermocouple is rejoined. This joint is invariably at the terminal strip of the instrument.  Question 16. What Are De-saturators? Answer : When, in some processes, e.g. batch processes, long transient responses are expected during which a sustained deviation is present the controller integral action continuously drives the output to a minimum or maximum value. This phenomenon is called ‘integral saturation of the control unit’. When this condition is met, then this unit is de-saturated.

 Question 17. Explain The Working Of Rotameter? Answer : Variable area meters are special form of head meters. Where in the area of flow restrictor is varied. So as to hold the differential pressure constant. The rota meter consists of a vertical tapered tube through which the metered fluid flows in upward direction. As the flow varies the ‘float’ rises or falls to vary the area of the passages that the differential across it balances the gravitational force on the ‘float’. The differential pressure is maintained constant. The position of the ‘float’ is the measure of the rate of flow.  Question 18. What Is The Working Principle Of The Magnetic Meter? Answer : An electric potential is developed when a conductor is moved across the magnetic field. In most electrical machinery the conductor is a wire. The principle is equally applicable to a moving, electrically conductive liquid. The primary device of commercial magnetic meters consist of straight cylindrical electrically insulated tube with a pair of electrodes nearly flush with the tube walls and located at opposite end of a tube diameter. This device is limited to electrically conducting liquids. The magnetic meter is particularly suited to measurement of slurries and dirty fluids.  Question 19. Explain The Mechanism Behind The Turbine Meter? Answer : Turbine meters consist of straight flow tube within which a turbine or fan is free to rotate about it s axis which is fixed along g the centre line of the tube. Mostly, a magnetic pick up system senses the rotation of the rotor through the tube walls. The turbine meter is a flow rate device, since the rotor speed is directly proportional to the flow rate. The output is usually in the form of electric pulses from the magnetic pick up with a frequency proportional to the flow rate.  Question 20. How Would You Choose Differential Range? Answer : The most common range for differential range for liquid measurement is 0-100. This range is high enough to minimize the errors caused by unequal heads in the seal chambers. It is also dependent on the differences in the temperature of the load lines. The 100 range permits an increased in capacity up to 400. While decrease down up to 20 by merely changing the range tubes or range adjustments.  Question 21. What Is The Use Of Single Seated Valve? Answer :

The single seated valve is used on smaller sizes where an absolute shut off is required. The use of single seated valve is limited by pressure drop across the valve in the closed or almost closed position.  Question 22. What Is The Use Of Double Seated Valve? Answer : In double seated valves the upward and downward forces on the plug due to reduction of fluid pressure are nearly equalized. It is generally used on bigger size valves and high pressure systems. Actuator forces required are less.  Question 23. What Is The Use Of Valve Positioner? Answer : Valve positioner can be used for following reasons: 1. 2. 3. 4. 5. 6. 7.

Quick action Valve hysteresis Viscous liquids Split range. Line pressure changes on valve Bench set not standard Reverse valve operations

 Question 24. What Are Primary Elements Of Measuring Pressure? Which Type Of Pressure Can Be Measured By These Elements? Answer : Primary elements of measuring pressure are: 1. 2. 3. 4. 5.

Bourdon Tube Diaphragm Capsule Bellows Pressure springs

These elements are known as elastic deformation pressure elements.  Question 25. Name Different Types Of Bourdon Tubes? Answer : Types of bourdon tubes: 1. C type 2. Spiral 3. Helix

 Question 26. What Are Different Types Of Control Valves? Answer : The commonly used control valves can be defined as follows: a. Depending on Action: Depending on action there are two types of control valves 1. Air to open 2. Air to close b. Depending on body: Depending on body there are 4 types of control valves 1. 2. 3. 4.

Globe valves single or double seated Angle valves Butterfly valves Three way valves

 Question 27. What Is Furnace Draft Control? Answer : Balanced draft boilers are generally used negative furnace pressure. When both forced draft and induced draft are used together, at some point in the system the pressure will be same as that of atmosphere. Therefore the furnace pressure must be negative to prevent hot gas leakage. Excessive vacuum in the furnace however produces heat losses through air infiltration. The most desirable condition is that the one have a very slight negative pressure of the top of furnace.  Question 28. What Is Intrinsically Safe System? Answer : Intrinsic safety is a technique for designing electrical equipment for safe use in locations made hazardous by the presence of flammable gas or vapours in the air. Intrinsically safe circuit is one in which any spark or thermal effect produce either normally or under specified fault conditions is incapable of causing ignition of a specified gas or vapour in air mixture at the most ignited concentration.  Question 29. Hat Is Zener Diode? What Is Voltage Regulator? Answer : The breakdown region of a p-n diode can be made very sharp and almost vertical diodes with almost vertical breakdown region are known a s zener diodes. A zener diode operating in the breakdown region is equivalent to a battery. Because of this current through zener diode can change but the voltage remains constant. It is this constant voltage that has made the zener diode an important device in voltage regulation.  Question 30. What Is Zener Diode? What Is Voltage Regulator?

Answer : The breakdown region of a p-n diode can be made very sharp and almost vertical diodes with almost vertical breakdown region are known a s zener diodes. A zener diode operating in the breakdown region is equivalent to a battery. Because of this current through zener diode can change but the voltage remains constant. It is this constant voltage that has made the zener diode an important device in voltage regulation. Voltage regulator: The output remains constant despite changes in the input voltage due to zener effect.  Question 31. What Is Force Balance Principle? State Some Of Its’ Advantages? Answer : Force balance principle: A controller which generates an output signal by opposing torque. The input force is applied on the input bellows which moves the beam. This crackles nozzle back pressure. The nozzle back pressure is sensed by the balancing bellows which brings the beam to balance. The baffle movement is very less about 0.002 for full scale output. Advantages: 1. Moving parts are fewer. 2. Baffle movement is negligible 3. Frictional losses are less  Question 32. What Is Motion Balance Principle? Answer : A controller which generates an output signal by motion of its parts. The increase in the baffle is to move towards the nozzle. The nozzle back pressure will increase. This increase in the back pressure acting on the balancing bellows, will expand the bellows. The nozzle is moved upward due to this. The nozzle will move until motion almost equals the input baffle motion.  Question 33. How Will You Test A Transistor With A Multimeter? Answer : 1. 2. 3. 4.

Emitter +ve of meter and base -ve output =Low resistance Emitter -ve of meter and base +ve output =High resistance Collector +ve and base -ve output =Low Collector -ve and base +ve output =Low

Emitter: Collector = High resistance PNP: Opposite Results  Question 34. Explain Ratio Control System?

Answer : A ratio control system is characterized by the fact that variations in the secondary variable don’t reflect back on the primary variable. A ratio control system is the system where secondary flow is hold in some proportion to a primary uncontrollable flow. If we assume that the output of a primary transmitter is A. and the output of the secondary transmitter is B, and that the multiplication factor of the ratio relay is K, then for equilibrium conditions which means set valve is equal to measured valve, we find the following relation: KA-B=0 or B/A = K where ‘K’ is the ratio setting off the relay.  Question 35. What Is Solenoid Valve? Where It Is Used? Answer : A solenoid is electrically operated valve. It consists of solenoid coil in which magnetic plunger moves. This plunger is connected to the plug and tends to open or close the valve. There are two types of solenoid valves: 1. Normally Open 2. Normally closed Use: It is used for safety purpose in different electric work.

Process Control And Instrumentation Interview Questions  Question 1. What Is Instrumentation? Answer : The technology which is used to measured and control the process system of plant is called instrumentation. It is branch of engineering.  Question 2. What Is Reynolds Number? Answer : We know with help of reynolds number what type of flow in fluid.  Question 3. Why Do We Use 4-20ma Signal Instead Of 0-10 Ma? Answer : To elevate zero so that we can come to know whether it is dead zero or from signal.

 Question 4. What Is The Difference Between Dry Leg And Wet Leg? Answer : Dry leg means in lab. And wet leg means in feild  Question 5. How Can We Calibrate A Positioner? Answer : A positioner is a device put into a valve to ensure that it is at a correct position of opening as per the control signal. An I/P converter only sends the opening/closing request to valve but can not confirm its position. Positioner senses the valve opening through a position feedback link connected to valve stem which is its input signal. I/P converter output is its setpoint input. The difference between these two is the error signal based on which the positioner positions the valve to correct position to reduce error to zero. Hence positioner is nothing but a pneumatic feedback controller. Controlled external supply air to positioner provides power to positioner to position a valve. Also positioner is used in a valve when valve operating signal range is different from I/P converter output range.  Question 6. Explain What Is The Working Principle Of The Magnetic Meter? Answer : An electric potential is developed when a conductor is moved across the magnetic field. In most electrical machinery the conductor is a wire. The principle is equally applicable to a moving, electrically conductive liquid. The primary device of commercial magnetic meters consist of straight cylindrical electrically insulated tube with a pair of electrodes nearly flush with the tube walls and located at opposite end of a tube diameter. This device is limited to electrically conducting liquids. The magnetic meter is particularly suited to measurement of slurries and dirty fluids.  Question 7. Tell Me The Mechanism Behind The Turbine Meter? Answer : Turbine meters consist of straight flow tube within which a turbine or fan is free to rotate about it s axis which is fixed along g the centre line of the tube. Mostly, a magnetic pick up system senses the rotation of the rotor through the tube walls. The turbine meter is a flow rate device, since the rotor speed is directly proportional to the flow rate. The output is usually in the form of electric pulses from the magnetic pick up with a frequency proportional to the flow rate.  Question 8. How To Choose Differential Range? Answer :

The most common range for differential range for liquid measurement is 0-100. This range is high enough to minimize the errors caused by unequal heads in the seal chambers. It is also dependent on the differences in the temperature of the load lines. The 100 range permits an increased in capacity up to 400. While decrease down up to 20 by merely changing the range tubes or range adjustments.  Question 9. What Is The Working Of Rota Meter? Answer : Variable area meters are special form of head meters. Where in the area of flow restrictor is varied. So as to hold the differential pressure constant. The rota meter consists of a vertical tapered tube through which the metered fluid flows in upward direction. As the flow varies the ‘float' rises or falls to vary the area of the passages that the differential across it balances the gravitational force on the ‘float'. The differential pressure is maintained constant. The position of the ‘float' is the measure of the rate of flow.  Question 10. Explain What Are De-saturators? Answer : When, in some processes, e.g. batch processes, long transient responses are expected during which a sustained deviation is present the controller integral action continuously drives the output to a minimum or maximum value. This phenomenon is called ‘integral saturation of the control unit'. When this condition is met, then this unit is de-saturated.  Question 11. Do You Know How Is Automatic Reference Junction Compensation Carried Out In Temperature Recorders? Answer : In automatic reference junction compensation, variable nickel resistor is used. As the temperature changes, so does its resistance. This reference junction compensator is located, so that it will be at the temperature of the reference junction. The reference junction is at the poset where the dissimilar wire of the thermocouple is rejoined. This joint is invariably at the terminal strip of the instrument.  Question 12. What Is Solenoid Valve? Where It Is Used? Answer : A solenoid is electrically operated valve. It consists of solenoid coil in which magnetic plunger moves. This plunger is connected to the plug and tends to open or close the valve. There are two types of solenoid valves: 1. Normally Open 2. Normally closed Use: It is used for safety purpose in different electric work

 Question 13. What Is Ratio Control System? Answer : A ratio control system is characterized by the fact that variations in the secondary variable don't reflect back on the primary variable. A ratio control system is the system where secondary flow is hold in some proportion to a primary uncontrollable flow. If we assume that the output of a primary transmitter is A. and the output of the secondary transmitter is B, and that the multiplication factor of the ratio relay is K, then for equilibrium conditions which means set valve is equal to measured valve. we find the following relation: KA-B=0 or B/A = K where ‘K' is the ratio setting off the relay.  Question 14. How To Test A Transistor With A Multimeter? Answer : 1. Emitter +ve of meter and base -ve output =Low resistance 2. Emitter -ve of meter and base +ve output =High resistance 3. Collector +ve and base -ve output =Low 4. Collector -ve and base +ve output =Low Emitter: Collector = High resistance PNP: Opposite Results  Question 15. What Is Motion Balance Principle? Answer : A controller which generates an output signal by motion of its parts. The increase in the baffle is to move towards the nozzle. The nozzle back pressure will increase. This increase in the back pressure acting on the balancing bellows, will expand the bellows. The nozzle is moved upward due to this. The nozzle will move until motion almost equals the input baffle motion.  Question 16. What Is Force Balance Principle? State Some Of Its' Advantages? Answer : Force balance principle: A controller which generates an output signal by opposing torque. The input force is applied on the input bellows which moves the beam. This crackles nozzle back pressure. The nozzle back pressure is sensed by the balancing bellows which brings the beam to balance. The baffle movement is very less about 0.002 for full scale output.

Advantages: a. Moving parts are fewer. b. Baffle movement is negligible c. Frictional losses are less  Question 17. What Is Zener Diode? What Is Voltage Regulator? Answer : The breakdown region of a p-n diode can be made very sharp and almost vertical diodes with almost vertical breakdown region are known a s zener diodes. A zener diode operating in the breakdown region is equivalent to a battery. Because of this current through zener diode can change but the voltage remains constant. It is this constant voltage that has made the zener diode an important device in voltage regulation. Voltage regulator: The output remains constant despite changes in the input voltage due to zener effect.  Question 18. What Is Intrinsically Safe System? Answer : Intrinsic safety is a technique for designing electrical equipment for safe use in locations made hazardous by the presence of flammable gas or vapours in the air. Intrinsically safe circuit is one in which any spark or thermal effect produce either normally or under specified fault conditions is incapable of causing ignition of a specified gas or vapour in air mixture at the most ignited concentration.  Question 19. What Is Furnace Draft Control? Answer : Balanced draft boilers are generally used negative furnace pressure. When both forced draft and induced draft are used together, at some point in the system the pressure will be same as that of atmosphere. Therefore the furnace pressure must be negative to prevent hot gas leakage. Excessive vacuum in the furnace however produces heat losses through air infiltration. The most desirable condition is that the one have a very slight negative pressure of the top of furnace.  Question 20. What Are Different Types Of Control Valves? Answer : The commonly used control valves can be defined as follows:

a. Depending on Action: Depending on action there are two types of control valves 1. Air to close 2. Air to close b. Depending on body: Depending on body there are 4 types of control valves 1. Globe valves single or double seated 2. Angle valves 3. Butterfly valves 4. Three way valves  Question 21. Name Different Types Of Bourdon Tubes? Answer : Types of bourdon tubes: 1. C type 2. Spiral 3. Helix  Question 22. What Are Primary Elements Of Measuring Pressure? Which Type Of Pressure Can Be Measured By These Elements? Answer : Primary elements of measuring pressure are: a. Bourdon Tube b. Diaphragm c. Capsule d. Bellows e. Pressure springs These elements are known as elastic deformation pressure elements.  Question 23. What Is The Use Of Valve Positioner? Answer : Valve positioner can be used for following reasons: a. Quick action b. Valve hysterisis c. Viscous liquids

d. Split range. e. Line pressure changes on valve f. Bench set not standard g. Reverse valve operations  Question 24. What Is The Use Of Double Seated Valve? Answer : In double seated valves the upward and downward forces on the plug due to reduction of fluid pressure are nearly equalized. It is generally used on bigger size valves and high pressure systems. Actuator forces required are less.  Question 25. What Is The Use Of Single Seated Valve? Answer : The single seated valve is used on smaller sizes where an absolute shut off is required. The use of single seated valve is limited by pressure drop across the valve in the closed or almost closed position.  Question 26. Name Different Parts Of A Pressure Gauge? Explain The Use Of Hair Spring In The Pressure Gauge? Answer : Pressure gauge includes following components: a. ‘C' type bourdon tube. b. Connecting link c. Sector gear d. Pinion Gear e. Hair spring f. Pointer g. Dial Use of hair spring: Hair spring is responsible for controlling torque. It is also used to eliminate any play into linkages.  Question 27. Tell Me How Is Flow Measured In Square Root? Answer : Flow varies directly as the square root of pressure. Thus, F=K of square root of applied pressure. Since this flow varies as the square root of differential pressure. The pressure pen does not directly indicate flow. Thus flow can be determined by taking the square root of the pen. Assume the pen reads 50% of the chart. So, flow can be calculated using the pen measure in the chart.

 Question 28. Explain How Can A D.p. Transmitter Be Calibrated? Answer : D.P. transmitter can be calibrated using following steps: 1. Adjust zero of Xmtrs. 2. Perform static pressure test: Give equal pressure on both sides of transmitter. Zero should not shift either side. If the zero shifts then carry out static alignment. 3. Perform vacuum test: Apply equal vacuum to both the sides. Zero should not shift. 4. Calibration procedure: Give 20 psi air supply to the transmitter and vent L.P. side to atmosphere. Connect output of the instrument to the standard test gauge. Adjust zero. Apply required pressure to the high pressure side and adjust the span. Adjust zero gain if necessary.  Question 29. What Is Bernoulli's Theorem. State Its Application? Answer : Bernoulli's theorem states that the ‘total energy of a liquid flowing from one point to another remains constant'. It is applicable for non-compressible liquids. For different types of liquid flow Bernoulli's equation changes. There is direct proportion between speed of fluid and its dynamic pressure and its kinetic energy. It can be used in various real life situations like measuring pressure on aircraft wing and calibrating the airspeed indicator. It can also be used to low pressure in the venturi tubes present in carburetor.  Question 30. Explain Why Is The Orifice Tab Provided? Answer : Following reasons justify for providing orifice tab: 1. Indication of orifice plate in a line 2. The orifice diameter is marked on it. 3. The material of the orifice plate. 4. The tag number of the orifice plate. 5. To mark the inlet of an orifice.  Question 31. Do You Know How Do You Identify An Orifice In The Pipeline? Answer : An orifice tab is welded on the orifice plate which extends out of the line giving an indication of the orifice plate.

 Question 32. Explain What Are Different Types Of Orifice Plates? State Their Uses? Answer : Different orifice plates are: 1. Concentric 2. Segmental 3. Eccentric Concentric: These plates are used for ideal liquid as well as gases and steam service. Concentric holes are present in these plates, thats why it is known as concentric orifice. Segmental: This plate has hole in the form of segment of the circle. This plate is used for colloidal and sherry flow measurement. Eccentric: This plate has the eccentric holes. This plate is used in viscous and sherry flow measurement.  Question 33. Why Thermo Wells Are Used? What Materials Are Used In Thermo Wells? Answer : In numerous applications, it is neither desirable nor practical to expose a temperature sensor directly to a material. Wells are therefore used to protect against damage corresion, arosion, aborsion and high pressure processes. A thermo well is also useful in protecting a sensor from physical damage during handling and normal operations. Materials used in thermo wells: Stainless steel, Inconel, Monel, Alloy Steel, Hastelloy  Question 34. Can You Explain The Burnout Feature? Answer : Burnout provides the warnsug feature of driving indicator at the end of scale, if the input circuit is open. A burnout resistor is provided which develops a voltage drop between the measuring circuit and amplifier. The polarity of the signal determines the direction of the servo drive upon an open circuit in the input. Upscale burnout: R value 10 M Downscale burnout: R value 22 M  Question 35. What Is Constant Voltage Unit? Answer :

The constant voltage circuit consists of a rectifier, CR and a filter capacitor. It is followed by two stages of zener regulation. Abridge configuration is provided to lamp line voltage zener regulation. Regulation 1 and regulation 2 provides relatively provide constant current. Resistors form a bridge that may remoment line voltage effects.  Question 36. Tell Me The Working Of An Enraf Level Gauge? Answer : Enraf level gauge is based on the ser powered null balance technique. A displacer serves as continuous level sensing element. A two phase ser motor controlled by a capacitive balance system winds unwinds the the measuring wire until the tension in the weight springs is in balance with the weight of the displaced part immersed in the liquid. The sensing system in balance measures the two capacitance formed by the moving central sensing rod provided by the two capacitor plates and the si plates.  Question 37. Do You Know The Working Of An Electronic Level Troll? Answer : The variation in level of buoyancy resulting from a change in liquid level varies the net weight of the displacer increasing or decreasing the load on the torque arm. This change is directly proportional to change in level and specific gravity of the liquid. The resulting torque tube movement varies the angular motion of the rotor in RVDT providing a rotor change proportional to the rotor displacement, which is converted and amplified to a D.C. current.  Question 38. Explain How D.p. Transmitter Can Be Applied To Open Tank? Answer : In open tank the lower pressure side is vented to the atmosphere. All pressure is applied to the high pressure side. This vessel pressure is measured through high pressure side.  Question 39. Do You Know How D.p. Transmitter Can Be Applied To Close Tank? Answer : In closed tank, bottom of the tank is connected to the high pressure side of the transmitter. Top of tank is connected to the lower pressure side of the transmitter. In this way vessel pressure can be measured.  Question 40. What Is The Function Of 3-way Manifold Valve? Answer : excessive pressure to your differential pressure transmitter, you could damage your instrument. This is known as over-ranging the transmitter.

A three-way manifold valve is a device that prevents the instrument from being over-ranged. It also allows the isolation of the transmitter from the process loop (an option which could be used generaly for maintenance or re-calibration or fitting new equipment).  Question 41. Why We Giving Input To Electronic Amplifier In Inverting Pin? What Is The Reason Behind That? Answer : if we need a phase shift than we give input n inverting pin or when we need to boost signal at higher level, i.e; using cascade stages of amplification(even) than we also use inverting pin.  Question 42. What Is Instrumentation Instrumentation Engineering? Answer : Instrumentation engineering is the engineering specialization focused on the principle and operation of measuring instruments which are used in design and configuration of automated systems in electrical, pneumatic domains etc. They typically work for industries with automated processes, such as chemical or manufacturing plants, with the goal of improving system productivity, reliability, safety, optimization and stability.  Question 43. What Is Instrumentation Control? Answer : In addition to measuring field parameters, instrumentation is also responsible for providing the ability to modify some field parameters. Some examples include: Device Field Parameter(s) Valve Flow, Pressure Relay Voltage, Current Solenoid Physical Location, Level Circuit breaker Voltage, Current.  Question 44. What Is Instrumentation Measurement? Answer : Instrumentation can be used to measure certain field parameters (physical values): These measured values include: * pressure, either differential or static * flow * temperature - Temperature_measurement * level - Level Measurement * density * viscosity

* radiation * current * voltage * inductance * capacitance * frequency * resistivity * conductivity * chemical composition * chemical properties * various physical properties  Question 45. Can We Use A Control Valve Without Positioner? Answer : Control valve can not be without positioner. The purpose of the positioner is to control the control valve stroke so as to keep the valve in desired position. The positioner receives signal from the controller, and send the boosted signal to the actuator to reach the desired position as and when the valve reaches the desired position the positioner cuts the boosted signal to the actuator and keeps the position.  Question 46. Why 4-20 Ma Signal Is Preferred Over A 0-10v Signal? Answer : Generally in a transistor some amount of voltage is required for turning it on. This voltage is the cut in voltage. Up to this voltage the exists a nonlinearity in its characteristics. Beyond this cut in voltage the char. of transistor is linear. This nonlinear region lays between 0-4ma, beyond 4ma it linear. This is why 4-20 ma range is used.  Question 47. What Is Remote Mount With Mta Option? (in Case Of Dual Sensor Vortex Flowmeter, Rosemount Has Written In Its Catalog Drawings)? Answer : Remote mount with MTA means MTA connector for mounting remote connection. MTA is the Connector used for connection. Generally we called it MTA Connector. There are many types of MTA connector such as MTA 100connectors, Mta 156 connectors etc.  Question 48. How To Write The Program For Single Push Button By Using Ladder Diagram? Answer : 1. Create a Push button 2. Connect a Counter series to PB

3. Create a compare button 4. Initialize 1 at one end 5. Counter output in another 6. Connect the Coil which has to be energized 7. Initialize 2 at one end 8. Counter output in another 9. Connect the Coil which has to be reenergized.

Industrial Instrumentation Interview Questions  Question 1. What Are The Process Variable? Answer : The process Variable are: 1. 2. 3. 4. 5.

Flow Pressure Temperature Level Quality i. e. % D2, C02, PH etc.

 Question 2. Define All The Process Variable And State Their Unit Of Measurement? Answer : 1. FLOW: Kg I hr, Litter I min, Gallon I min. M3 I NM3 I HR. (GASES) 2. PRESSURE: Force acting per unit Area. P = F/A Units: Bar I Pascals I Kg I CM I, Pounds 3. LEVEL: Different between two heights. Units: Meters, M M, C M, %. 4. TEMPERATURE: It is the degree of hotness or coldness of a body. Units : Degree Centigrade, Degree Farenheit, Degree Kelvin, Degree Rankin. 5. QUALITY: It deals with analysis PH, % C02, % 02, Conductivity, Viscosity.  Question 3. What Are The Primary Elements Usedfor Flow Measurement? Answer : The primary elements used for flow measurement are: 1. 2. 3. 4. 5. 6.

Orifice Plate. Venturi tube. Pitot tube. Annubars. Flow Nozzle. Weir & Flumes.

 Question 4. What Are The Different Types Of Orifice Plates And State Their Uses?

Answer : The different types of orifice plates are: 1. Concentric. 2. Segmental. 3. Eccentric. CONCENTRIC: The concentric orifice plate is used for ideal liquid as well as gases and steam service. This orifice as a hole in concentric and hence known as concentric orifice. Eccentric & Segmental: The eccentric orifice plate has a hole eccentric. The use this is made in viscous and sherry flow measurement. The segmental orifice place has the hole in the form segment of a circle. This is used for colloidal and sherry flow measurement.  Question 5. How Do You Identify An Orifice In The Pipe Line? Answer : An orifice tab is welded on the orifice plate which extends our of the line giving an indication of the orifice plate.  Question 6. Why Is The Orifice Tab Provided? Answer : The orifice tab is provided due to the following reasons: 1. 2. 3. 4. 5.

Indication of an orifice plate in a line. The orifice diameter is marked on it. The material of the orifice plate. The tag no. of the orifice plate. The mark the inlet of an orifice.

 Question 7. What Is Bernoulli’s Theoram And Where It Is Applicable? Answer : Bernoulli’s theoram states the “total energy of a liquid flowing from one point to another remains constant.” It is applicable for non compressible liquids.  Question 8. How Do You Identify The H. P. Side Or Inlet Of An Orifice Plate In Line? Answer : The marking is always done H. P. side of the orifice tab which gives an indication of the H.P.side.

 Question 9. How Do You Calibrate A D. P. Transmitter? Answer : The following steps are to be taken which claribrating : 1. Adjust zero of the Xmtrs. 2. Static preasure test: Give equal pressure on both sides of the transmitter. Zero should not shift. If it is shifting carry out static alignment. 3. Vaccum test: Apply equal vaccum to both the sides. The zero should not shift. Calibration Procedure:     

Give 20 psi air supply to the transmitter. Vent the L.P. side to atmosphere. Connect output of the Instrument to a standard test gauge. Adjust zero. Apply required pressure to high pressure side of the transmitter and adjust the span. Adjust zero again if necessary.

 Question 10. What Is The Seal Liquid Used For Filling Impulse Lines On Crude And Viscous Liquid? Answer : Glycol.  Question 11. How Do You Carry Out Piping For A Different Pressure Flow Transmitter On Liquids, Gas And Steam Services? Why? Answer : Liquid lines: On liquid lines the transmitter is mounted below the orifice plate. Since liquids have a property of self draining. Gas Service: On gas service the transmitter is mounted above the orifice plate because Gases have a property of self venting and secondly condenlate formation. Steam Service: On steam service the transmitter is mounted below the orifice plate with condenlate pots. The pots should be at the same level.  Question 12. An Operator Tells You That Flow Indication Is More? How Would You Start Checking? Answer : 1. First flushing the transmitter. Flush both the impulse lines. Adjust the zero by equalizing if necessary. If still the indication is more then. 2. Check L.P. side for choke. If that is clean then. 3. Check the leaks on L.P. side. If not. 4. Calibrate the transmitter.

 Question 13. How Do You Do A Zero Check On A D.p. Transmitter? Answer : Close one of the valve either H.P. or L.P. open the equalizing valve. The O/P should read zero.  Question 14. How Would You Do Glycol Filling Or Fill Seal Liquids In Seal Pots 7 Draw And Explain? Answer : The procedure for glycol filling is : 1. 2. 3. 4. 5. 6. 7. 8.

Close the primary isolation valves. Open the vent on the seal pots. Drain the use glycol if present. Connect a hand pump on L.P. side while filling the H.P. side with glycol. Keep the equalizer valve open. Keep the L.P. side valve closed. Start pumping and fill glycol. Same repeat for L.P. side by connecting pump to H.P. side, keeping equalizer open and H.P. side isolation valve closed. 9. Close the seal pot vent valves. 10. Close equalizer valve. 11. Open both the primary isolation valves.  Question 15. How Do You Calculate New Factor From New Range Using Old Factor And Old Range? Answer : New Factor = _!New Range Old Factor = _IOld Range Flow = K_!Range Q = Factor X Unit Flow New Factor = Old Factor I _IOld Range X _/New Range.  Question 16. How Will You Vent Air In The D.p. Cell? What If Seal Pots Are Used? Answer : 1. Air is vented by opening the vent plugs on a liquid service transmitter. 2. On services where seal pots are used isolate the primary isolation valves and open the vent valves. Fill the line from the transmitter drain plug with a pump.  Question 17. Why Is Flow Measured In Square Root? Answer :

  

Flow varies directly as the square root of different pressure F = K square root of ΔP. Since this flow varies as the square root of differential pressure the pen does not directly indicate flow. The flow can be determined by taking the square root of the pen. Say the pen reads 50% of chart.