Installation Guide Of Eg

SECTION 1 - Safey Precautions Before operating any generator system, read the Operator's Manual to become familiar with your equipment. Safe and efficient operation can only happen if the equipment is properly operated and maintained. No generator manufacturer or installation contractor can anticipate every potential hazard involved with the installation and use of these type of systems. The warnings, decal and labels attached to the equipment and used in this Manual can not cover all hazards. Use of methods or procedures other than those recommended by the equipment manufacturer must satisfy you that it is safe for you or others to follow. The following symbols are highlighted to alert you of conditions that are potentially dangerous to the operator, installation/service/repair personnel, or the equipment. 1-1. General Safety Precautions DANGER

This symbol warns of hazards which will result in severe or lethal personal injury.

WARNING

This symbol refers to a hazardous or unsafe practice which has the potential to result in personal injury or product/property damage.

CAUTION

This symbol warns of immediate hazards which will result in severe or lethal personal injury.

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Keep equipment clean and properly maintained. Normal maintenance and servicing of equipment is a prerequisite to a functional, safely operated machine.

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Use common sense, read the instructions and information in this manual carefully, and check for other local safety rules that require compliance.

1-2. Installation Precautions •

Be safety conscious. Read all operational, safety and installation information before attempting to install or operate any generator equipment.

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This equipment should be installed, operated, serviced, and repaired by qualified personnel only. The installation and interconnection of this equipment to facility wiring and other equipment must be done by a competent, qualified craftsperson who is familiar with applicable standards and codes governing the installation.

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Installation methods, practices, or procedures that are unauthorized or done improperly are dangerous and could result in serious personal injury or damage to property and equipment.

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Installation, operation, servicing and repair of electrical power generators and their related equipment must be done in accordance to applicable codes, standards, regulations and laws. The National Fire Prevention Association (NFPA), National Electric Code

(NEC), Occupational Safety and Health Administration (OSHA) regulations, local industrial codes and requirements must be complied with in the use and servicing of this equipment. WARNING

FUEL AND FUMES ARE FLAMMABLE. A fire or explosion could result from violation of recommended practices or procedures

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An open flame, smoking, or welding near a generator is a potential fire hazard. Internal combustion engine fuels are flammable.

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Ensure all fuel fittings are properly connected and not leaking. Periodic inspection is required to ensure no leaks develop over time.

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Fuel connection at the engine should be made with an approved flexible fuel line. Use of copper piping for flexible lines is not recommended as copper work hardens and becomes brittle.

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Never fill fuel tanks while the engine is running, unless tanks are outside the engine room. When fuel comes in contact with a hot engine or exhaust system, there is possibility of a fire or explosion.

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Under certain conditions storage batteries will expel explosive hydrogen gas. Do not allow smoking, welding or sparks in the vicinity of any storage battery. Adequate ventilation must be provided around batteries. Battery racks must also be grounded to minimize static charges. DANGER

EXHAUST GASES ARE LETHAL

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Ensure the exhaust system is installed properly and adequate ventilation is provided. Exhaust gases must be safely piped away from the unit to an area not used by people. The engine consumes oxygen and the exhaust given off by the engine contains carbon monoxide gas. Carbon Monoxide is a deadly, lethal gas.

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The installation must have adequate ventilation. DANGER

MOVING PARTS CAN KILL

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While equipment is running, stand clear of moving parts.

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When in service certain automatic start units are capable of starting at anytime. Disable control and power switches before maintaining, servicing or repairing these units.

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Before starting work on a self-starting generator, disconnect the starting battery. Disconnect the negative (-) battery cable first to prevent accidental shorting.

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Ensure all fasteners are secure. Tighten hardware and keep all guards in position over fans, impellers, or other moving parts.

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If adjustments must be made while the unit is running, use extreme care around moving and hot parts. Hot parts include engine and exhaust system, muffler, pipes, flexible exhaust pipe section, etc.. WARNING

ELECTRICAL SHOCK CAN CAUSE SEVERE INJURY OR DEATH

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Wire gauge sizes of electrical wiring, cables, and facility circuits must be of sufficient size to handle the maximum electrical current (ampacity) of circuits. Refer to generator system's User Manual to determine appropriate cable/wire size.

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Remove electrical power before removing any generator's protective panels or touching any electrical components.

SECTION 2 - Locations The location for a generator is dependent on applicable codes and associated support systems for the generator such as ventilation, wiring, fuel, and exhaust. The following factors should be considered: •

The ideal location for any generator is away from extreme ambient temperatures and where the generator is protected from adverse weather conditions. It is recommended that generator be as close to the load it is supporting as possible.

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The structure the Gen-Set (Generator Set) will be set upon must be strong enough to support the weight of the Gen-Set, its' auxiliary equipment, and other equipment mounted on the structure.

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The structure must meet a 1 hour non-combustion fire rating.

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The installation site must be clean, dry and not subject to flooding.

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Because of excessive ambient temperatures associated with the use of stand-alone metal sheds from exposure to sunlight, a concrete pad with a supported roof and an outside security enclosure (fence) to protect the unit from vandalism, birds, rodents, and other small animals is recommended.

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The Gen-Set generates heat while running. Installing the Gen-Set in a tightly enclosed building or shed is not recommended. The site must provide for adequate cooling and ventilation with a minimum of duct work. Adequate ventilation for a generator is specified in cubic feet per minute.

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The site must permit engine exhaust gases to be piped away to an area that is uninhabited by people or animals. Care must be given to ensure that exhaust gases do not re-enter an occupied area.

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The site must provide adequate acoustical noise and vibration isolation.

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The outside site must provide access to the generator to allow for maintenance, service, and repair. A three foot (.914 meter) service clearance around the unit is recommended.

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Fuel supply and ease of refueling must be taken into consideration.

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Adequate normal and emergency lighting must be provided in any installation.

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When mounting a generator outside on a roof or next to a building the generator must be at least 3 feet from any combustible wall and 5 feet from any opening(i.e. doors, windows, vents, & ducts).

2-1. Ground/Floor Loading The foundation for the generator must support the total weight of the generator. This includes fuel, oil, and the weight of any associated support systems. Plan for 3 feet (1 Meters) of access around the generator for maintenance, service and repair. When calculating the floor loading, ensure the fuel weight, cooling system fluids (where applicable), piping, pumps, power cables/runways and supporting structures are included in the calculations. Most user's manuals do not include the weight of the fuel tanks since most are sold less tank. SECTION 3 - Mounting A concrete foundation with anchored mounting bolts, is recommended. Steel Beams are an acceptable alternative. Foundations help in the servicing and repair of Gen-Set's and protect the unit from moisture that could occur from seepage. The concrete base that the generator is mounted to should be separate and independent from the surrounding structure. The following applies to concrete bases: •

A Single (See Figure 1)or Double (See Figure 2) pedestal base may be used. A height of at least 6 inches higher than floor level is recommended. Figure 1- Single Pedestal Concrete Mount

Figure 2 - Double Pedestal Concrete Mount

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A double pedestal base allows easier cleaning under most generator's.

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Double pedestals provide better access for inspecting for oil or fuel tank leaks.

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The generator should be retained to the pedestal base with fasteners that are recommended by the generator set manufacturer.

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The concrete base should extend beyond the generator's "Footprint" by at least 12 Inches (305 mm) on all sides.

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The higher the mounting base is made, the easier the unit will be to work on when performing maintenance, service, or repairs. Typically bases are required to be raised at least 6 inches (153 mm) above floor level. Placing the unit higher than 6 inches sometimes has the advantage of making it easier to change the unit's oil.

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Passing fuel lines and electrical conduit for a "stub-up" through the concrete base is a standard practice of gen-set installers.

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Concrete foundations are typically mixed by volume. The typical ratio of cement, sand, and aggregate is 1:2:3 with a maximum 4 inch (102 mm) slump and 28 day compressive strength of 2500 psi (173 kPa).

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A generator can typically be mounted to a combustible floor or roof, dependent upon code, however, the surface beneath the engine and beyond the engine to a minimum distance of 12 inches (305 mm) must be covered with a non combustible insulation and a minimum of 24 gage sheet metal between the insulation and the generator. See Figure 3. Figure 3. Combustible Floor and Roof

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Optional vibration isolators beyond those already built in the generator also help reduce transmitted noise, however, it is recommended that one verify that the generator manufacturer recommends the use of an isolator.

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Insulation must be a non-combustible material, typically a Fiberglas mat.

SECTION 4 - Ventilation 4-1. Outdoor Installations - Air Cooled Units •

Air cooled unit draws cooling air from different ends of the unit to cool the system, dependent upon the units cooling system design. Check with the generator's manufacturer to determine the optimal cooling method for the system. Factors such as climate and direction of prevailing winds must be considered in an outdoor installation.

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If your generator is expected to be in temperatures lower than -20oF(-29oC) consult the generator sets factory, a cold weather package may be required.

The following general rules apply: •

Where strong prevailing winds are anticipated, face the engine end away from the wind.

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Plan the installation carefully to prevent the cooling air vents on the generator from becoming clogged by leaves, grass, snow, etc. Figure 4 . Typical Outside Small Generator Installation

4.2 Indoor Installations - Air Cooled Units When a generator is installed and operated in an indoor environment, adequate ventilation for heat dissipation and combustion is required. Ventilation is typically done through the use of an air inlet, air outlet/exhaust fan, and/or other ventilation openings. The following rules apply: •

When ever possible, face the generator air inlet openings away from the wind. The wind can prevent the air intake louver from opening on start up.

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The air inlet must be capable of moving enough air through the room to provide the correct minimum CFM (cubic feet per minute) cooling for generator as specified by the generator's manufacturer. (This means the generator's air inlet opening size will be greater than the generator's room exhaust fan outlet.)

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Locate air inlet, ventilation and air outlet openings in a structure so that already exhausted air will not be drawn back into the building.

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Louvers, screening, expanded metal and other materials used to cover air openings are a restriction to air flow. This restriction must be compensated for by making the air opening size proportionally larger.

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When possible, position the engine end of air cooled generators in line with the air inlet per the manufacturer's recommendation.

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When possible, position liquid cooled engines with the engine end in line with the exhaust outlet per the manufacturer's recommendation. The reason or this recommendation is that the air moving through a liquid cooled system is typically pulled past the engine and through the generator's radiator. The generator's radiator is placed so that the air is ducted out of the generator's room.

4-3. Ventilation Exhaust Fans and Air Inlet Louvers Some indoor installations may require the use of one or more exhaust fans, to provide adequate ventilation during generator operation. The following rules apply: •

Exhaust fans must have the proper capacity for the specific application. In addition, the fans must be located so that engine exhaust gases will not re-enter the building.

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Power is required to operate the exhaust fan. Typically, AC is provided from an DC/AC inverter or UPS to operate the exhaust fan and open air inlet louvers.

4-4. Ducting of Air The engine cooling fan moves a large volume of air during operation. This heated air must be expelled to the outside of any structure housing a generator. The following rules apply to the ducting of heated engine air out of a building: •

Whenever possible, use no ductwork at all. Simply position the inlet air duct so that air will be drawn directly over the generator and expelled horizontally to the building exterior (outdoors).

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If duct work must be used between the generator installation location and the building air outlet opening, keep such ductwork as short as possible with a minimum number of bends.

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Construct air outlet duct work of self-supported sheet metal.

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Never locate the air outlet opening of a structure close to adjacent buildings or walls as noise is amplified when air is expelled in large volumes.

Figure 5. Typical Indoor Ventilation Duct

Figure 6. Typical Small Generator Indoor Installation

Figure 7. Typical Indoor Larger Generator Installation

Roof mount radiators on liquid cooled units is sometimes done where the installation location of the unit can not dissipate the heat generated by the unit during operation. Roof mount radiators is beyond the scope of this publication. 4-5. Louvers, Screening And Expanded Metal When louvers, screening or expanded metal are used to cover air openings in buildings housing generators, consideration must be given that these materials do not restrict the free flow of

cooling air. Any restriction must be compensated for by making the actual opening size proportionately larger. Louvers: Either fixed or movable louvers may be installed on the air openings in a structure that houses a generator. The installer must make sure that the total square inches of free air inlet opening is sufficient to limit the heat rise in the room to prevent the room temperature from exceeding the generator 's operating temperature. Figure 8. Louver

Find the actual free air opening as follows: •

Multiply the height of a single louvered opening by its width, to find the opening area of one louvered opening.

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Multiply the opening area of the single louvered opening by the total number of louvered openings to find total free air inlet area. Figure 9. Screening and Expanded Metal

Screening and Expanded Metal: Screening and expanded metal may be used to cover air inlet and outlet openings in a structure that houses the generator. These materials also offer a restriction to the free flow of cooling air, which must be compensated for by making the actual air opening in the structure proportionally larger. Screening and expanded metal are usually assigned a "free air inlet area" value by the manufacturer, which is given as a percentage. To find the actual size of the air inlet opening needed, proceed as follows: •

Find the area of the generator's inlet air duct, by multiplying the air duct height by its width.

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Divide the inlet air duct area by the percentage of free air inlet area for the particular screening or expanded metal to be used. The result is the required size of the air inlet opening in the building.

Example 1: If the required inlet air opening area on a particular generator is 400 square inches and the building air opening is to be covered with screening having a 70% "free air inlet area": Divide 400 square inches by 0.70, to obtain 576 square inches. Actual air inlet opening size in the building should be equal to or greater than 576 square inches. (An opening that measures 24 X 24 inches (576 square inches) would be adequate in this case to achieve the required 1125 Cu. ft/minute (31.86 Cubic Meters/Min.). Example 2: The required inlet air opening area on a particular generator is 500 square inches and the building air opening is to be covered with screening having a 70% "free air inlet area": Divide 500 square inches by 0.70, to obtain 714 square inches. Actual air inlet opening size in the building should be greater than 714 square inches. (An opening that measures 27 X 27 inches (729 square inches) would be adequate in this case to achieve the required 2000 Cu. ft/Minute (39 Cubic Meters/Min.). SECTION 5 - Fuel 5-1. Gasoline

For gasoline egine generators, Unleaded or Regular gasoline with a lower octane rating than 85((RON/MON)/2) may cause pre-detonation (knocking) which can damage the engine. Regular gasoline can be used, however, unleaded gasoline is preferred because it reduces pollution and combustion chamber deposits. See the generator's engine owner's manual for fuel information or contact the generator set's manufacturer. WARNING

ENGINE FUEL can cause fire or explosion.

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Do not operate the engine without the cranking battery connected.

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Do not disconnect the cranking battery while the engine is running.

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Stop engine by turning the Key Switch to OFF before checking oil or adding fuel.

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If fuel is spilled, clean up immediately and dispose of contaminated materials properly.

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Do not refuel if engine is hot or running.

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Do not refuel near sparks or open flame.

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Do not smoke while refueling.

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Do not fill fuel tank to the top; allow room for expansion.

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Fuel consumption varies from one engine to another. Different brands of fuel, operating conditions, condition of engine, etc., also affect the fuel consumption. CAUTION

POOR QUALITY, LOW OCTANE FUEL can damage the engine.

IMPORTANT: •

Use clean, fresh, unleaded gasoline with at least 85 octane rating.

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Do not mix oil with the gasoline.

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Do not use gasohal or gasoline alcohol fuel blends.

5-2. Gaseous Fuels Typically on LP Gaseous or Natural Gas powered unit the unit will run on either vaporous fuel source. Most gaseous fuel units are set up for a specific number of ounces of line pressure (a.k.a. as a corresponding number Inch Water Column) with some type of threaded pipe hook up. Note: Use of gaseous fuels decrease the amount of total power the generator is capable of producing by as much as 20 percent, dependent upon thermal content of fuel in your specific area. Refer to Section 8 for Gaseous Fuel Systems. 5-3. Diesel Fuel Piping and Filtration The basic requirements of a diesel engine fuel system are adequate piping, proper selection of filters for the application and completely air-tight joints, with a minimum number of fittings to prevent air from entering the fuel lines, especially in installations where the fuel tank is lower

than the pump. 5-3. A. Piping to the Tank Vacuum at the transfer pump inlet must be avoided. If an auxiliary pump is used, pressure at the transfer pump must not be less than 0 p.s.i. nor greater than 5 p.s.i.(typical). Pressure after the return line connector assembly must not exceed 5 p.s.i. unless called for in the pump or system specification. NOTE: The return line must never be piped back to the transfer pump inlet side. Both supply and return line should be connected to standpipes in the tank with the opening for each 2 inches minimum from the bottom of the tank to allow space for water and sediments to settle and to eliminate siphoning problems. 5-3.B. Filter Requirements 1. A pleated paper type filter with large area and minimum pressure drop capable of filtering out 75 - 80% of five micron particles should be used. A Master Filter is recommended since it provides sufficient area for long life and two stage filtration for maximum protection. 2. Where water in the fuel is known to be a problem, a Master Separator is recommended. Contact the generator manufacturer for a recommended filter. 5-3.C. Maximum Pressure Drop Pressure drop across clean filters should not be more than 2.5 inches of mercury (1.2 p.s.i.) at full load. Pressure drop in the supply system exceeding 10 inches of mercury (4.9 p.s.i.) because of dirty filters or other restriction usually will affect pump and engine performance, (erratic operation, low power, engine stall). 5-4. Fuel Consumption Fuel consumption is typically specified in the generator's user manual and is specified in a quantity of fuel consumed per hour based on a specified load. Refer to the generator's user manual for expected fuel consumption, which is based upon a specific load. While the generator's manufacturer may not be able to predict the consumption for your site because of the differences in the typical load, by site, an estimate a full load is typically given. A simple fuel consumption model that is a "ball park" predictor of fuel consumption is as follows: Based on experience, a generator at no load typically uses about half of the fuel of a generator at full load. The ratio of output power from a generator to the amount of fuel consumed is almost linear. Consumption on diesel fueled generators is somewhat less than gasoline. Fuel Consumption = (Estimated Load/Maximum Generator Power Output) X .5 X Maximum Fuel Consumption + 50% of Maximum Fuel Consumption Assuming Maximum fuel consumption = 1 Gallon/Hour Minimum fuel consumption = .5 Gallon/Hour At a 50% load, Fuel Consumption = (((50 Amps/100 Amps) X .5 Gallon) + .5 Gallon) = (((.5) X .5) + .5) = .75 Gal./Hr.

Other factors that need to be taken into account are the temperatures of the areas where the fuels are stored are as follows: •

Diesel gels at lower temperatures. It is advisable to use the lowest temperature rated fuel all year around. The reason for this is that the generator will typically run only at scheduled maintenance test times. If higher temperature rated fuel is used, by time the lower temperature fuel is put into the tank, the fuel blend will be less than desired at the time you need the lowest temperature rating.

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Use of LP is a problem at lower temperatures. At 20oF the amount of fuel in an LP tank that is available to vaporize decreases dramatically. Rule of thumb for LP is that the amount of fuel available is about 50 percent of the amount of fuel in the tank. In short, at cold temperatures, only 50 percent of the fuel in the tank is available for the generator.

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At -36oF, LP does not vaporize. This means no fuel will be available for use.

SECTION 6 - Electrical System There are a number of different generator systems and typical loads in the context of electrical systems. Most systems, unless they contain automated swtich gear, have a means of disconnect between the generator and the load. This is typically a transfer switch or disconnect. Ensure the contacts on the switch are rated for the size of your system. System schematics are beyond the context of this tutorial at this time. 6-1. General (Electrical System) Generators are rated for a maximum current in Amps and power output in Kilowatts. Typically power outputs can vary between different models. The output is dependent upon fuel type, ambient temperature and altitude of the installation. Of same model types using different fuels, Gasoline units will have the highest output followed by gaseous fuels (Natural Gas and Liquid Petroleum(Vapor withdrawal). LP is about 95% of that of gasoline and natural gas at about 85% of gasoline. These units typically derate at about 3% per 1,000 ft (334 meters) starting at about 3,000 feet (1,000 meters) and an additional 1% for every 10 degrees over 78 degrees F. This is fairly common for all asperating engines. Diesel units derate more for temperature and altitude. Diesels typically derate at about 4% per 1,000 ft (334 meters) starting at sea level and an additional 1% for every 10 degrees over 78 degrees F. At higher elevations, this power loss can be significant. Circuits to carry power from the generator needs to be sized accordingly. Distance of the generator to the load (Typically a UPS) will also effect wire size. The conduit entryway for the generator is typically specified for a nominal size and may need to be increased in size if you are required to go to the maximum wire size. Flexible liquid tight metallic conduit should be used. Direct Current (D.C.) Generators typically require a significantly larger cable size from the generator to the load (typically UPS batteries) in order to compensate for voltage drop. Voltage drop is a function of the resistance of the wire over the distance from the source to the load. The typical recommedation for D.C. generators is to keep the generator as close to the load as possible. Refer to the generators manufacturer's recommendations. Refer to N.F.P.A. 70, also known as the National Electric Code (NEC) for cable sizing tables. When mounting electrical panels, a 3 foot clearance is required and the use of an emergency light to illuminate the unit during operation is typically required. Power for the emergency light should be from both the primary utility and the generator. This is highly recommend so that in

the event of a malfunction there is a light source to see to work on the unit. Refer to your local building and electrical codes to ensure compliance. Use of powered exhaust fans and powered louvers for ventilation is typical for indoor installations. Emergency power will be needed operate the auxillary devices. Make sure the generator is sized large enough to cover the load and the auxillary equipment. 6-2. Conductor Sizing Connection This information is dependent upon your generator output and intended load. When connecting cables to the generator, unless instructed differently by the equipment manufacture, make connections at the generator first. Make the connections at the load last. Failure to do so may constitute a fire or safety hazard. All ampacities are typically calculated at 75 o C (Celsius)(167 o F(Fahrenheit) in the conductor size charts. Building wire conductors should be rated at 90oC(194oF) to allow for different ambient temperatures that these conductors may pass through. All conductors are typically required by electrical code to be copper. The recommended conductor sizes are based on maximum current. Ampacities are found in NEC Article 310, Table 310-16. Conductor resistances are found in NEC Table 8 "Conductor Properties". Direct Current (D.C.) generators require larger output power cables than comparable A.C. generators due to voltage drops in the cable caused by increased resistance. Most A.C. Generators require the use of transfer switches. Refer to manufacturer's installation instructions and recommendations. Return to Table of Contents Go to Section 7 Tips on Hooking up a Generator (genset) to a Uninterruptible Power System (UPS)

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Amazon.com now has tools, tooling and gas powered generators in their Amazon.com's Home Improvement Store. Click onAmazon.com's Home Improvement Store SECTION 7 - Exhaust System 7-1. General (Exhaust System) Generator engines give off deadly carbon monoxide gas through their exhaust systems. Carbon monoxide gas, if breathed in sufficient concentrations, can cause unconsciousness or death. Exhaust gases must be piped safely away from any room or enclosure that houses a generator and to a well ventilated area where people will not be endangered.

Besides the possibility of carbon monoxide poisoning, exhaust piping becomes extremely hot during operation and remains hot for a long time after shutdown. For that reason, the following precautions are necessary: •

Avoid contact with hot engines, exhaust manifolds, exhaust piping and mufflers. Any of these can cause severe burns.

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Where piping must pass through combustible walls or ceilings, special precautions must be taken to prevent fire or heat damage such as using heat thimbles through walls and ceilings.

7-2. General Rules for Exhaust Systems When installing an exhaust system for a generator, the following rules should be considered: •

Exhaust piping should be of wrought iron or steel having adequate strength and durability.

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Exhaust fittings may be of cast iron. A 9 inch spacing (10 inches (250mm) recommended) from the exhaust pipe and walls is also required by most local codes.

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Low points in horizontal runs of piping should be provided with condensation traps, as well as condensation drains.

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Piping and mufflers must be properly supported and connected.

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A flexible length of exhaust pipe is required between the engine exhaust manifold and rigid exhaust piping.

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Exhaust piping must be terminated safely outside a structure that houses a generator, in such a way that hot gases and sparks will be discharged harmlessly and will not blow against any combustible surface or material.

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Exhaust piping must not terminate under loading platforms, structures, or near any opening in a building.

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Where necessary, exhaust piping must be guarded and/or insulated to prevent burns.

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Provide a clearance of at least 9 inches (229mm)(10 inches (250mm) recommended) between exhaust piping and any combustible material.

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Keep exhaust piping well clear of fuel tanks, fuel lines, etc.

7-3. Routing Exhaust Piping Through Combustible Walls •

Exhaust piping that passes through any combustible wall or partition must be guarded at the point of passage by:

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A ventilated metal thimble that is at least 12 inches in diameter larger than the piping, or

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Metal or burned fire clay thimbles built in brickwork that provides not less than 8 inches of insulation between the clay thimble and any combustible material.

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Thermal insulation or protective guards are typically required for exhaust pipes/system by national and local codes to protect users from burns. Figure 10. Wall Thimble

7-4. Routing Exhaust Piping Through Combustible Roofs Exhaust piping that passes through any combustible roof must be separated from the roof by a ventilated metal thimble that is at least 6 inches in diameter larger than the piping. The thimble must extend at least 9 inches (229mm)(10 inches (250mm) recommended) above and below roof construction.

Figure 11. Roof Thimble

7-5. Rain Cap A rain cap is recommended on the end of the exhaust pipe. The rain cap is attached to the end of the pipe and opens due to the pressure from the exhaust discharge force. The rain cap protects the exhaust system from the environment when the system is not running. 7-6. Spark Arrestor Use of a spark arrestor is required by the U.S. Department of Forestry if located on lands under their jurisdiction. The spark arrestor is recommended in areas where combustible materials may ignite such as dry grass, leaves, or other combustible materials. 7-7. Exhaust Back Pressure The exhaust back pressure of the generator when measured at full load must not exceed the manufacturer's recommendations. The size of exhaust pipe, number and type of ends and fittings together with the selection and location of muffler determine exhaust back pressure. A typical 90 degree bend in an exhaust system is equal to adding 8 feet (2.67 meters) of pipe. SECTION 8 - Gaseous Fuel Systems 8-1. General (Gaseous Fuel Systems) Some generators are equipped with fuel systems that utilize Liquefied Petroleum (LP) or Natural Gas as a fuel. Local fuel gas codes may vary widely. For that reason, it is recommended that a local gas distributor or installer be consulted when installing a gaseous fuel supply system. In the absence

of local fuel gas codes and regulation, booklets published by the National Fire Protection Association (NFPA) may be used as sources of information. The installer must ensure that the correct fuel delivery system is installed, and that applicable standards and codes are strictly complied with. 8-2. Advantages of Gaseous Fuels Use of Natural and LP gas as a fuel may result in a slight power loss. However, that disadvantage is usually compensated for by the many advantages of gaseous fuels. Some of the advantages of gaseous fuels are: Low residue content, resulting in minimum carbon formation. •

Reduced sludge build-up in engine oil.

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Reduced valve burning, as compared to gasoline.

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No "wash down" of engine cylinder walls during start up.

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No tetra-ethyl lead to foul spark plugs and other engine parts.

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Excellent anti-knock qualities.

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Reduced amounts of contaminated residues.

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A nearly homogeneous mixture in engine cylinders.

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Fuel can be stored for long periods without breakdown.

8-3. Gaseous Fuel System Variations Any one of four different types of gaseous fuel systems may typically be installed by the factory on your generator system, dependent upon the model. These are: •

Liquefied Petroleum (LP) gas vapor withdrawal.

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Liquefied Petroleum (LP) gas liquid withdrawal.

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Natural Gas.

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Dual Natural and LP gas (Additional regulator and hardware are not standard on most generators Contact the generator's manufacturer if you need this option).

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Combination Gas-Gasoline systems (Additional regulator and hardware are not standard on the generator systems. (Contact the manufacturer if you need this option).

8-4. Properties of Gaseous Fuels Natural Gas: Is lighter than air and tends to settle in high places. Natural gas is found in the gaseous state only at normal ambient conditions. Natural gas is highly explosive and accumulations of the gas can be ignited at the slightest spark. For that reason, adequate ventilation is absolutely essential and fuel lines must be free of leaks. Local fuel/gas codes usually dictate the maximum pressure at which natural gas can enter a structure. A primary regulator is required, to reduce the pressure of the delivered gas to the reduced pressure required by code. LP Gas: Is heavier than air, tends to settle in low places. The gas is highly explosive and the slightest spark can cause an explosion. LP gas is usually supplied in pressure tanks as a liquid, but is found in gaseous form at normal atmospheric temperature and pressure. It may consist of

(1) butane, or (2) propane, or (3) a mixture of these two gases. Fuel suppliers may fill the supply tank with a mixture made up primarily of butane in warm weather. Butane may not provide sufficient vapor pressure in colder weather and more propane may have to be added to the mixture. The ratio of butane to propane is especially important when a large outdoor supply tank is used. LP gas must be converted to its vapor state before it enters the engine carburetor. 8-5. Natural Gas Fuel System The maximum pressure at which natural gas can enter the building is established by code and may vary from area to area. The gas distribution company will usually provide piping from the main distribution line to the standby generator site. A primary regulator is needed to reduce gas supply pressures to the required safe level before the gas enters a building. Such a regulator may or may not be provided by the gas supplier. It is the responsibility of the gas supplier to ensure that sufficient gas pressure is available to operate the primary regulator. Gas outlet pressure from the primary regulator to the standby generator's shutoff valve should typically not exceed approximately 0.50 pounds per square inch (psi), or 14 inches of water column. Optimum supply pressure to most small generator's shutoff valve is 11 inches of water column. Depending on the characteristics of the specific shutoff valve in use, the valve may or may not open at supply pressures greater than 0.50 psi (14 inches water column). Install a flexible length of fuel line between rigid piping and the Generator engine's natural gas connection point. Natural gas is delivered to the primary regulator. From the primary regulator, in most installations, the gas flows through a solenoid operated fuel shutoff valve, a pressure reducing valve and the engine's natural gas carburetor. The shutoff valve is electrically energized open during startup and running, is de-energized closed on shutdown. The carburetor measures engine air flow and meters gas to the engine based on throttle setting and load. The carburetor also provides a positive gas shutoff. 8-6. LP Gas Vapor Withdrawal System This type of system utilizes the vapors formed above the liquid fuel in the supply tank. Approximately 10-20 percent of the tank capacity is needed for fuel expansion from the liquid to the vapor state. Ambient temperatures around the supply tank must be high enough to sustain adequate vaporization or the system will not function properly. In addition to the cooling effects of ambient air, the vaporization process itself provides an additional cooling effect. Vapor withdrawal systems are generally more suited for smaller engines that need less fuel. When ambient temperatures are low and fuel consumption is high, the vapor withdrawal system may not function efficiently. This is particularly true with larger engine machines. Many LP gas and Natural Gas vaporous fuel systems are identical as a demand regulator is used to provide fuel to the engine. 8-7. LP Liquid Withdrawal System This type of system delivers gas in liquid form to a generator. The liquid fuel must then be vaporized before it is delivered to the engine carburetor. Liquid withdrawal (LP) gas systems usually employ a "vaporizer-regulator" to convert the liquid to its vapor state. A "vaporizer-regulator" is mounted in the air flow of the engine to provide heat to the regulator for fuel vaporization.

LP liquid withdrawal is typically used for equipment used in remote locations where size and availability of refilling the tank is limited. Liquid withdrawal is also used for trailered and construction site equipment. 8-8. Dual Natural/LP Gas Fuel System In some areas, the cost of Natural gas may be reduced considerably by procuring the gas on "interrupted service" rates. Such "interrupted service" can be obtained by using LP gas as an emergency fuel whenever Natural gas is not available.. Automatic changeover is accomplished by using two regulators - a line pressure regulator for natural gas and a vacuum operated regulator for LP gas. The differences in pressures compensates for the greater BTU value of LP gas. During operation on Natural gas, a 5 inch (water column) (typical) pressure exists in the common line to the carburetor. This pressure closes the LP gas regulator. Loss of Natural gas pressure causes loss of pressure in the line; the LP gas regulator then opens to admit LP gas into the system. A separate power mixture adjustment in the LP gas line provides precise setting of air/fuel ratios for each of the two fuels. Changeover is automatic with the engine operating. 8-9. Gaseous Fuel System Piping The following general rules apply to piping used in gaseous fuel systems: •

Piping should be of black iron.

•

Piping should be rigidly mounted and protected against vibration.

•

Install an approved length of flexible hose between the generator fuel line connection point and rigid piping.

•

Piping must be of the correct size to maintain required supply pressure under varying conditions, especially when fuel in gaseous form is being supplied (Natural gas and LP gas vapor withdrawal).

•

Installed piping must be properly purged and leak tested, in accordance with applicable standards.

NOTE: In the absence of local purging and leak test standards, NFPA No. 54 may be used as a guide. 8-10. Gaseous Fuel Pipe Sizes A "Gas Flow Pipe Sizing Chart" (Table 8-1) is provided below. Use the chart to determine the correct piping diameter in gaseous fuel systems (such as Natural gas and LP gas vapor withdrawal type). To find the proper pipe diameter, the installer must know (a) the length of the gas piping run, and (b) the cubic feet of gas needed by the generator when under full load. First, find the length of the piping run on the chart. From the pipe length figure on the chart, move horizontally across the chart until you reach a number that is just higher than the cubic feet of gas needed under full load. From the cubic feet of gas figure, move straight up vertically in the chart to the pipe diameter given in that vertical column. This is the pipe size required.

LP Gaseous Fuel Example: A small 16 horse power generator when operating at full load requires a supply of 51 cubic feet per hour of LP gas. Length of the piping run from the supply tank is 60 feet. Propane gas having a specific gravity of 1.5 and with a multiplier of 0.633 is used (Table 8-2). From the pipe length in the chart, trace horizontally across to "86" (the first number larger than 51 cubic feet). Moving vertically upward in the chart, a 3/4 inch pipe is needed. Applying the chart conversion factor (86 x 0.633=54.44) and the 3/4 inch pipe is still adequate. Natural Gas Example: A small 16 horse power generator operating at full load requires 115 cubic feet per hour of Natural gas. Length of the piping run from the supply tank is 75 feet. Natural gas having a specific gravity of 0.65 and with a multiplier of 0.962 (Table 8-2) is to be used. From the pipe length in the chart, trace horizontally across to "155" (the first number larger than 115 cubic feet). Moving vertically upward in the chart, a 1 inch pipe is required. Apply the conversion factor (155 x 0.962=149.1) and the 1 inch pipe is still adequate. Table 8-1. Gas Flow Pipe Sizing Chart Length 1-1/4 1-1/2 2-1/2 1/2 In. 3/4 In. 1 In. 2 In. 3 In. 4 In. 6 In. 8 In. of In. In. In. (12.7m (19.05 (25.4m (50.8m (76.2m (101.6 (152.4 (203. pipe (31.75 (38.1m (68.5m m) mm) m) m) m) mm) mm) 2) (FT/M) mm) m) m) 15/4.57

76

172

345

750

1220

2480

3850

6500

13880

28700

7900 0

30/9.14

52

120

241

535

850

1780

2750

4700

9700

27370

5585 0

45/13.7 2

43

99

199

435

700

1475

2300

3900

7900

23350

4560 0

60/18.2 9

38

86

173

380

610

1290

2000

3450

6800

19330

3950 0

75/22.8 6

70

155

345

545

1120

1750

3000

6000

17310

3530 0

90/27.4 3

77

141

310

490

1000

1560

2700

5500

15800

3225 0

105/32. 00

65

131

280

450

920

1430

2450

5100

14620

2985 0

120/36. 58

120

270

420

860

1340

2300

4800

13680

2798 0

150/45. 72

109

242

380

780

1220

2090

4350

12240

2500 0

180/54. 86

100

225

350

720

1120

1950

4000

11160

2280 0

210/64. 01

92

205

320

660

1030

1780

3700

10330

2110 0

240/73. 15

190

300

620

970

1680

3490

9600

1974 0

270/82. 30

178

285

580

910

1580

3250

9000

1861 0

300/91. 44

170

270

545

860

1490

3000

8500

1766 0

450/137 .16

140

226

450

710

1230

2500

7000

1442 0

600/182 .88

119

192

390

900

1030

2130

6000

1248 0

Table 8-2. Chart Conversion Factors Specific Gravity

Multiplier

Specific Gravity

Multiplier

Specific Gravity

Multiplier

0.50

1.100

0.700

0.926

1.200

0.707

0.55

1.040

0.800

0.867

1.400

0.655

0.60

1.000

0.900

0.817

1.500

0.633

0.65

0.962

1.000

0.775

1.700

0.594

Note 1: Use of elbows increases pressure drop on fuel lines. A 90 degree elbow adds 3 to 8 feet of equivalent length to your pipe estimate. Note 2: Typical Specific Gravity for Natural Gas is 0.65. Note 3: Typical Specific Gravity for LP is 1.5. Back to Table of Contents Go to APPENDIX A - Applicable Codes Tips on Hooking up a Generator (genset) to a Uninterruptible Power System (UPS)

Introduction There are many people in the generator and UPS industries that have tried to operate engine driven alternating current (A.C.) generator sets (gen-sets) and uninterruptible power systems (UPS) together. Although some systems are successful, there are problems that can occur. This article should provide insight into the problems of using a gen-set to power a UPS as well as provide enough information to possibly save the reader from a problem installation. Achieving and maintaining adequate control of frequency and line noise is a common issue in generator design and use. Unless the gen-set is sized 2 to 3 times the size of the UPS, and the UPS is about 75 percent loaded, the UPS may never switch from the inverter (battery power) to generator power. Another factor is that there is a great deal of line noise from small generators

compared to utility line power. This can also cause the UPS to stay on inverter until the batteries go dead. To address these problems, Best Power Technology, Inc., a fairly well known U.S. UPS supplier, started a DC generator product line. They have since dropped that product line due to a take over by a UPS competitor who did not want to be in the generator business. When preparing to connect a gen-set to a UPS, first check with the UPS manufacturer for recommendations on using their UPS with a generator. Sizing and compatibility issues should be addressed before even considering hooking a gen-set to the UPS. Loading and the ability of the generator to regulate the load, possibly the hardest issues to deal with, should be considered. In addition, the type of power plant and alternator used in the gen-set can effect whether the equipment will work together or not. For instance, Diesels/turbine engines work better than gasoline/liquid propane (LP) and Natural gas (NG) engines. It has been noted on gen-sets that single-phase alternators work better than three phase alternators. Turbo-charged engines work better than normally aspirated engines, as well as being better at higher altitudes. Fuel injected engines work better than engines with carburetors (Aspirated engines use carburetors). See Figure 1 below for a block diagram of a typical gen-set/UPS installation.

Figure 1. A Typical Generator - UPS Installation [Back to Index]

Sizing Considerations Tables 1 and 2 provide generator sizing and loading recommendations for various sizes of UPSs. These recommendations are based on UPSs and gen-sets from several manufacturers, and are more rules of thumb based on experience with connecting gen-set and UPSs together than absolute rules. The two tables differ in the fuel type of the gen-sets engines. The reason that a background load is shown in the tables is two fold. First, the additional load helps the generator regulate better. Second, in an emergency situation, it is always a wise move to put in emergency lighting, and is an electrical code requirement. Caution is advised when operating fluorescent lights from the UPS for emergency lighting. Preferably, power the fluorescent lights from the generator and have some incandescent emergency lights running from the UPS. Fluorescent lights will sometimes flicker, especially if the UPS is one that is a double conversion unit that uses a Ferro-resonant transformer. As improvements in UPS and generator technologies take place, these recommendations may become less relevant.

Gasoline/LP/NG Fuel Gasoline/LP/NG Gasoline/LP/NG Background Background Single Phase Three Phase Load Load Generator Generator

UPS KVA

KW

KVA

KW

KW

KVA

KW

0.5 to 3.5

10

12

2

10

12

2

4

10

12

2

10

15

2

5

13

16

2

15

19

2

7

16

20

3

19

24

2

10

24

30

4

29

36

4

12

30

38

5

36

45

6

18

46

57

7

55

68

8

Table 1. Gasoline/LP/NG Fuel Gen-sets

Diesel Fuel UPS

Diesel Diesel Background Background Single Phase Three Phase Load Load Generator Generator

KVA

KW

KVA

KW

KW

KVA

KW

0.5 to 2

5

7

1.5

5

7

1.5

2.5 to 3.5

5

7

1.5

6

8

1.5

4

6

8

1.5

8

10

1.5

5

8

10

2

10

13

2

7

10

12

2

13

16

2

10

14

18

2.5

19

24

3

12

18

23

3

24

30

4

18

28

34

4

37

46

6

Table 2. Diesel Fuel Gen-sets From Tables 1 and 2, note that the size of the gen-set is significantly larger than the UPS. There are a number of reasons. Besides the obvious losses due to line loss, there are inefficiencies involved every time another piece of equipment is brought into the equation. One of the biggest factors is that the generator needs to be sized to handle the start up of the largest load, not just the continuous load. Based on calculations and manufacturers specifications, the gen-set recommendations look like they are larger than needed. However, if the generators engine can't get up to speed and running, for any reason, the system will fail. [Back to Index]

Start Up Load / In Rush Current When a gen-set is being used to put power directly into the battery bank of the UPS, as shown in Figure 3, the load can exceed the gen-sets ability to supply power. The UPS, in holding the load, starts to deplete battery power immediately, at the start of the outage. By the time the gen-set is up and running, and prepared to go on-line, the battery bank has lost a considerable amount of power. At the instant power is provided to the battery charger, the charger is trying to power a battery bank that acts like a very large capacitor and the in rush of current into the batteries takes all the power available from the battery charger. This has been known to stop the engine on some gen-sets. This has also been known to start a "stop-restart cycle" where the gen-set never gets running to power the load and the UPS batteries finally run down and the UPS shuts down. A work-around for the current in-rush problem is to limit the amount of current the batteries can draw from the charger. Putting a Current Shunt in-line with one of the battery leads can do this. Another option is, if the gen-set has the capability of auto-start from sensing the UPS battery bank float voltage, set the float voltage on the battery bank at a higher voltage to get the gen-set to start sooner also may help. [Back to Index]

Other Generator Tips Other gen-set related caveats that allow the gen-set to work with the UPS are as follows: 1. If installing a three-phase generator, install the UPS across the generator phase that is monitored by the generator's voltage regulator. 2. Adjust the governor of the generator so that the line frequency doesn't deviate by more than plus or minus 3 hertz. 3. Install additional ballast loads such as emergency lighting that are equal to 15% of the KW rating of the gen-set. The ballast loads share the generator with the UPS and stabilize the

generator so that the frequency is less erratic. The loads should be stable and continuous such as lighting or electric heaters. In other words, do not use air conditioners or air compressors for a background load. See Figure 2 below.

Figure 2. Adding Background Load as a Ballast to Improve Regulation [Back to Index]

UPS Tips In hooking a UPS to a gen-set, the following should be reviewed and considered: 1. When connecting a generator to the UPS, make sure that there is a disconnect switch between the UPS and generator. A disconnect switch is usually required by code as well as a serviceability and safety factor. In most cases, a means of disconnect is required. If soft wired, you may be able to get away with a plug and socket (i.e. Anderson Connectors); however, check with the authority having jurisdiction. 2. Ensure that the UPS has enough power to operate any ventilation fans or other required peripheral emergency equipment connected to the UPS during an outage. It is common for the gen-set ventilation fans and/or powered intake louvers to be powered from the UPS. 3. When using an existing generator with a UPS, the UPS may not run on the generator's power because the UPS's software is telling the UPS that it has poor input power. Gen-set power compared to most commercial utility power, is very erratic. Before giving up, look into buying a battery charger and hook the battery charger directly into the UPS's battery bank. See item #4 below. 4. When hooking power from a battery charger directly into the UPS battery bank, make sure to check with the UPS manufacturer to find out if the UPS's inverter is rated for continuous duty. There is nothing worse than burning up the UPS inverter because it was only designed to run as long as the manufacturers factory installed internal batteries would carry it. Always verify with the UPS manufacturer that their units have been rated for continuous duty. At this time, I know that the UPPIand Best Power Ferrups units have been rated for continuous duty, however, it is always a good idea to confirm that your particular unit is rated for it. Due diligence has saved a

number of people a lot of time, money and warranty head aches from their power equipment suppliers. See Figure 2 below.

Figure 3. Using a Battery Charger to Avoid Generator Regulation Issues. 5. If using a battery charger that is powered from a generator, ensure that the battery charger provides the correct voltage for the UPS battery bank, and is large enough to handle the load. This means that the battery charger has to produce enough power out to handle the UPS input requirements as well as to compensate for any other inefficiency. [Back to Index]

Other Alternatives If a UPS and gen-set still do not operate correctly, there may still be a way to salvage the project, depending upon whether the generator has sufficient power to hold the load and whether the problem is a regulation issue. The first alternative is to simply add additional (background) load to the gen-set. This will help to tighten regulation, though this is not always effective.

The second alternative is more expensive. This alternative requires some retrofitting expertise to replace the governor on the generator with a better grade governor or an electronic controller such as a Barber-ColmanTM. The generator supplier may have an alternative governor available, though most small gen-sets typically do not. Some mechanical engineering work may also be required to fit an electronic controller onto the gen-set if the supplier doesn't have an off-theshelf solution. [Back to Index]

UPS's for Sale For those looking for a UPS or Power Conditioner: Click here to use the UPS/Power Conditioner Quote Request / Sizing - Applications Assistance Contact Form to obtain help sizing a Uninterruptible Power Products or Best Power UPS for your needs from Uninterruptible Power Products, Inc..

GENERATOR OPTIONS, CONTROL PANELS, REMOTE MONITORING, AND ATTACHMENTS Cat Electric Power provides a full line of options and attachments to customize your Caterpillar Generator Set to fit your exact needs. For a complete list and specifications, please contact your Cat Dealer.

Generator Options Include: •

Anti-Condensation Heater

•

Excitation System

•

Permanent Magnet Generator

•

Voltage Regulator

Generator Control Systems & Monitoring Options Include: •

Auto-start Control Panel

•

Auxiliary Controls

•

Digital Control Panel

•

Electronic Governor

•

Key start Control Panel

•

Load Sharing

•

Remote Annunciator

•

Remote Monitoring Software

•

Shunt Trip

•

Single / Dual Circuit Breakers

•

Speed Control

Generator Accessories Include: •

Battery Heater

•

Coolant Heater

•

Engine Exhaust System

•

Exhaust Silencer / Muffler

•

External Fuel Tank

•

High Output Battery

•

Integrated Fuel Tank Base

•

Lube Oil Drain Pump

•

Lube Oil Sump Heater

•

Seismic Vibration Isolator

•

Sound Attenuated Enclosure

•

Static Battery Charger

•

Sub-base Fuel Tank

•

Weatherproof Enclosure

DIESEL GENERATOR SET FEATURES & SPECIFICATIONS Cat Diesel Generator Set Features: •

Ratings from 12kW to 17,460kW

•

Emissions compliance with most worldwide regulations

•

Simple to specify and purchase

•

Easy to install and operate

•

Wide range of factory-designed options

•

Low life-cycle costs

•

Excellent transient response and steady state performance

•

World-class fuel efficiency

•

Single source for complete power solutions

•

Turnkey support from the Cat® Dealer network

Generator Options Include: •

Anti-Condensation Heater

•

Excitation System

•

Permanent Magnet Generator

•

Voltage Regulator

SWITCHGEAR OPTIONS The benefit of Caterpillar's vast experience in power generation is fully realized in its generator switchgear offering. Available from 600V through 15 kV, Cat® switchgear provides a harmonized system solution by being able to integrate all elements of monitoring and control of a Caterpillar® generator set in a single-source package. For integration of Caterpillar generator sets into a customer's facility, Caterpillar offers switchgear suitable for applications ranging from single standby/load management to multi-unit utility paralleling installations. In any of these cases, Caterpillar switchgear can offer remote communication capabilities for monitoring and control of your total system. Caterpillar switchgear employs a feature rich microprocessor based control system that is combined with an easy to use touchscreen operator interface panel. The entire system can be controlled from the switchgear-mounted touchscreen, or it can be controlled/monitored from a remote site through a personal computer.

Caterpillar offers three standard switchgear products that can support a wide variety of applications or can provide a custom designed system to meet your specific site's needs as required. Our XLM series products supports transfer between the utility source and generator bus, as well as affording capability for parallel operation with the utility for load management applications. The EGP series supports paralleling on an isolated generator bus and is commonly used in prime power or emergency standby systems. Finally, our LM series supports single unit paralleling with utility for load management and peak shaving applications.

AUTOMATIC TRANSFER SWITCHES (ATS) 50/60 Hz 600 V Class, 40-4000 Amps Caterpillar® offers a broad range of automatic transfer switch products that are positioned to support virtually any type of emergency power application from simple, single ATS installations to highly complex, multi-ATS/generator switchgear systems. Today every standby generator set that is sold requires at least one ATS, and some cases require multiple units. Available in sizes ranging from 40 through 4000A, there is a Cat switch to suit every project's needs. Consider: •

CTX series for residential and light commercial applications.

•

CTG series for overall general applications with limited attachments

•

CTS series for applications a wide range of attachments and configurations.

CTG Series & CTS Series meet the requirements of NFPA 110, 99, and 70.

Automatic Transfer Switch Features Include: •

Mechanically held contactor

•

Available in 2, 3, and 4 pole versions

•

Rating range from 40 to 4000 Amps

•

UL, IEC, and CSA listed

•

NEMA 1, 3R, 4, 4X, and 12 enclosures

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UNINTERRUPTIBLE POWER SYSTEMS (UPS) Caterpillar knows the importance of quality power to your operation. Whether supporting critical processes or defending servers from harmful power problems, Caterpillar's uninterruptible power supply systems will provide years of low maintenance protection. Yielding the lowest operating costs in the industry, Caterpillar's UPS system will provide the peace of mind that comes from knowing that Caterpillar is standing beside you in your efforts to grow your business. Currently offering uninterruptible power supply systems from 150kVA to multi-megawatt solutions, Caterpillar integrates a battery free UPS with its market leading generator sets, switchgear and automatic transfer switches to deliver a world class integrated system. Caterpillar's world wide dealer network makes service and support locally available and timely. Click here to find a Caterpillar Dealer near you or use the left navigation to learn

more about the Cat UPS, the uninterruptible power supply with the highest power density in the world.

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Number of Cylinders

» 4 in line

BHP CONT (PS)

» 75.5

Bore x Stroke (mm)

» 104x113

Displacement (Ltr)

» 3.839

Comp. Ration

» 17.5:1

Oil Sump Cap. (Ltr)

» 7.5

Aspiration

» T.C

Cooling System

» Water Cooled with Radiator

Electricals

» 12 Volts DC

Alternator

» STAMFORD / ELGI/ CROMPTON

Voltage Reg.

» +or-5% with Slip rings / + or – 1% with AVR

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» 415 V

Frequency

» 50 Hz

Power Factor

» 0.8

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Change over switch allows switching between mains supply and standby generators for emergency services and remote locations

Question : I have bought a generator, and would like to connect it to my house in case of mains failure. What do I need to do?

•

Answer : When using a generator as an alternative supply to the mains, there are

several precautions that must be observed. •

It is vital that the generator is completely isolated from the mains supply. This ensures that the generator is not attempting to power up the whole neighborhood, but also ensures that it does not electrocute a utility worker trying to restore the mains supply.

•

To achieve this, a double-pole, break-before-make, changeover switch must be installed by a qualified electrician. The Briggs & Stratton manual transfer switch is ideal for this application.

•

This should be fitted between the electricity meter and the building consumer unit. The switch connects the building to either the mains supply or to a lead which can be plugged into the generator.

•

Most buildings now have an RCD built into the consumer unit. This is configured to operate from the mains supply with an earthed neutral, and not from a generator with a floating earth. To utilize this protection device, it is necessary to modify the generator so that it is configured in the same way as the mains supply.

•

This is a simple modification for a qualified electrician, involving adding a link wire from the neutral terminal to the earth terminal. It is recommended to make this connection in the plug that is to be used to connect to the generator. This ensures that the generator is unmodified when it is disconnected from the house, and therefore remains safe.

•

The plug should be labeled “Do not connect to mains: Neutral-Earth link fitted”. The lead between the generator and the transfer switch is not protected by the RCD, it is therefore recommended to use a steel armored cable for this connection. Finally a local low-impedance earth spike needs to be installed

Q & A of the Day - Temporary genset earthing and protection 2007-11-14 Back

Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This first Question of the Day, on BS 7671 Section 551 - temporary genset earthing and protection, is answered by SELECT:

Genset in cellar - install to BS 7671 Section 551. Question: I've been asked whether it is possible to install a 5KVA backup generator to supply

emergency power during power outages. The supply is single-phase PME taken from a three-phase service head in an outbuilding/workshop. The supply then runs under the drive via 25mm two-core SWA (with earthed sheath) cable to a cellar. In the cellar, the earth is not connected to the MET of the house, which has an earth rod and a 100mA Type-S RCD. I believe that this is because the Ze reading at the house end of the SWA is over 1.5ohm. My thinking was to connect the generator to a break before make switch, connect the neutral to an earth rod installed beneath the SW and feed the SWA via an 30mA RCD and a fused isolator to the house CU. Can you see any problems with this approach? Answer: The arrangements you describe appear to be generally satisfactory provided you meet the requirements of BS 7671 Section 551. The following are some particular points to note: •

Ensure the earth electrode resistance is satisfactory - It should be less than 200ohm where possible.

•

The changeover switching arrangement (double-pole) should meet the requirements of Regulation 551-06-01.

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To prevent danger or damage to equipment, ensure that the requirements of Regulation 55102-03 are met.

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Alternator control system Document Type and Number: United States Patent 5754032 Abstract: A control system for controlling an alternator driven by an engine, for generating electric power, has a changeover switch for selectively switching destination of electric power generated by the alternator to a plurality of electric loads having respective different load voltage values. An ECU controls switching operation of the changeover switch and controls the alternator electric power, according to a direction in which the changeover switch has been switched. The ECU detects voltage of the alternator electric power when the destination of the alternator electric power is to be switched from a first electric load having a higher load voltage value of the plurality of electric loads to a second electric load having a lower load voltage value of the same, and causes the changeover switch to switch the destination of the alternator electric power from the first electric load to the second electric load after it is determined that the voltage of the alternator electric power has been changed from a predetermined higher voltage value to a predetermined lower voltage value

Brushless alternator Document Type and Number: United States Patent 4647806 Abstract: A brushless alternator consisting of interconnected stator coils disposed in stator plates and surrounding the main winding of the rotor and including rectifiers coupled to the stator coils. The rotor is on a shaft supported within the housing of the alternator, and includes an exciter with shaft-mounted rectifiers for supplying a DC voltage to the main winding of the rotor. The exciter field coil is spool wound on a cylindrical core that is contained within the exciter stator, that is attached to thealternator housing. The field coil has a concentric opening for slidably receiving the rotor shaft. The exciter rotor armature does not rotate, but is affixed to the alternator housing and surrounds the outer

periphery of the exciter field coil. The main winding of the rotor has a cylindrical sleeve extending from one end to engage and support the exciter rotor armature in alignment with the exciter stator.