Mr Zhang Wei Trnslt.docx

C&I 1.

What do you need to do to protect your equipment? 1) Apply for protection and withdrawal in advance. 2) Execution protection operation card 3) Perform two-person custody

2.

Briefly explain the causes of measurement errors?

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The reasons for the measurement error are: 1) Error caused by measurement method 2) Measurement tool, instrument error 3) Error caused by changes in environmental conditions 4) Measure the error caused by the level of personnel and observation ability 5) Error caused by the change of the measured object itself

3. What preparations should the instrument be prepared before investing? A: 1) Check the secondary door, the pipe and joint should be connected firmly. The secondary door and the sewage door should be closed, the joint lock nut should not leak, the packing should be filled with appropriate amount, and the operation hand wheel and fastening screws and washers are completely intact. 2) Pressure gauges and fixing clips should be firm 3) The electrical contact pressure gauge should check and adjust the signal device section 4. A:

DCS system history station function? 1) Historical data is configured offline. 2) Historical data collection. 3) Historical data shows printing. 4) Historical data dump.

5. PLC digital module check A: The output loop requires the output relay to operate reliably, the device to operate correctly, and the I/O module status indication to be correct. The host computer is displayed correctly. The input loop requires that the feedback is correct and the module indicator is correct. The feedback between the upper computer and the lower device can be one-to-one and accurate.

Electric 1. What is work ground? A: Working ground refers to the connection of some equipment in the power system to the earth metal directly or through arc suppression coils, reactors, resistors, etc., called working ground. 2.

Why is there still electricity in a short time after the cable line is powered off? What method is used to eliminate? A: The cable line is equivalent to charging when a capacitor line is running. When the power is lost during power failure, the accumulated charge on the core cannot be completely released. If it is touched by hand, it will cause people to feel electricity. The method of elimination is to discharge the ground to the ground. 3. What should you watch out for when measuring insulation resistance near live equipment? A: (1) When measuring the insulation resistance near the live equipment, the position of the surveyor and the shaker must be properly selected to maintain a safe distance so as not to touch the live part of the watch lead or lead support; (2) when moving the lead, Care must be taken to prevent staff from getting an electric shock. 4. A:

What are the main reasons for the overheating of the motor during operation? 1) The motor is overloaded and the stator current is too large. 2) The stator winding runs out of phase. 3) The power supply voltage is too high or too low. 4) The motor air duct is blocked or the fan is damaged.

5. The long-term allowable current carrying capacity of the cable is mainly determined by several factors. A: 1) Long-term allowable operating temperature of the cable. 2) Thermal performance of the cable itself.

Boiler 1. When replacing pipes, elbows and valves, what items should be checked? A: 1) Check whether the material meets the design requirements; 2) Whether there are factory certificates, inspection standards and test data; 3) Pay special attention to whether the temperature and pressure levels meet the requirements. 2. What are the reasons for the low output of the fan? A: (1) The gas composition changes or the gas temperature is high, so that the density is reduced; (2) the outlet pipe damper is blocked; (3) the inlet pipe damper or the net cover is clogged; (4) the impeller inlet clearance is too large or the blade Severe wear; (5) the speed becomes lower. 3. What is the swelling of the pipe that usually occurs in those parts? A: It usually occurs on the tube rows of the superheater and reheater high temperature flue gas area, especially the first few rows of tubes of the flue gas inlet, and the tubes in which the steam in the tube is insufficiently cooled. It is also possible for the water wall tube to swell. 4. What are the reasons for the increase in the temperature of the rotating mechanical bearing? A: The reasons are low oil level, lack of oil or no oil; high oil level, excessive oil quantity; unqualified or deteriorated oil quality (impurities in oil); insufficient or interrupted cooling water; oil ring without oil or oil, bearing Defective or damaged. 5. Coal mill coal breaking treatment A: 1. Reduce the inlet and outlet temperatures of the coal mill; 2. Unblock the falling coal pipe and the original coal hopper; 3. Eliminate the failure of the coal feeder

Turbine 1.

What are the reasons for the heating of the pump packing? The reasons for the heating of the pump packing are: 1) The packing pressure is too tight or the surrounding tightness is uneven. 2) The radial clearance between the shaft and the packing ring and gland is too small. 3) Insufficient or broken water.

2.

What are the maintenance items for low-pressure heaters? 1) Water room and tube sheet cleaning inspection. 2) Heat pipe to check for leaks and plugging. 3) Water level gauge inspection.

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3. What is stress relaxation? A: Under the long-term action of high temperature and stress, if the total deformation is constant, the stress of the part will gradually decrease with time. This phenomenon is called stress relaxation. 4.

Why does the regulating valve allow a certain amount of leakage? What tests do you need after the overhaul? A: The regulating valve generally has a certain leakage flow (refer to the flow when the regulating valve is fully closed). This is mainly due to a certain gap between the valve core and the valve seat. If the gap is too small, it is easy to jam, making the operation difficult and even damaging the valve. Of course, the leakage flow when the valve is fully closed should be small, generally controlled at 5% of the total flow inside.

5. What are the mechanical losses of centrifugal pumps? A: The mechanical loss of the centrifugal pump is bearing. The shaft seal friction loss and the impeller disc friction loss (the answer is similar to the calculation)