Faults and troubleshooting of inverter power suppl

2022-09-23
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Faults and troubleshooting of inverter power supply and power supply components in large pump stations

inverter power supply has 6kV main circuit working power supply and 380V control working power supply

(I) power control schematic diagram

6kv main circuit working power control schematic diagram, 380V control power working schematic diagram see Figure:

diagram

diagram

(II) power supply device

1 6kV main circuit working power supply device

(1) vehicle type knife switch

(2) vehicle mounted tubular fuse

(3) vehicle mounted vacuum contactor

(4) vehicle mounted butterfly arrester

(5) vehicle mounted insulation support

(6) 6kV cable

(7) inverter household cable insulation support

(8 oil leakage of oil circuit system generally occurs in buffer valve, oil return valve, oil delivery valve, oil pump and pipeline.Power connection wire

(9) Surge suppressor

(10) transformer

2 380V control circuit working power supply device

(1) drawer knife switch

(2) air circuit breaker

(3) 380V power cable

(4) inverter power control switch

(5) inverter heater power control switch

(6) control power transformer

(7) power connection wire

(I) 6kV power supply voltage instability fault

1 Fault phenomenon

the motor has uncontrollable sudden drop and rise in speed, the frequency converter in operation suddenly trips, and the display has no abnormal display

2. Fault inspection process

see figure for fault inspection process

figure

3 Check the precautions

(1) whether it is affected by other load starts or faults

(2) check 6kV power supply equipment and do a good job of secondary isolation

(3) safety protection measures should be taken when checking live equipment

(4) live operation should be supervised by someone in strict accordance with the operating procedures

(II) power supply overvoltage fault

1 Fault phenomenon

during operation, the frequency converter suddenly trips, and the display shows over voltage fault

2. Fault inspection process

see figure for fault inspection process

figure

3 Inspection precautions

(1) when the positive fluctuation of input power supply voltage exceeds the allowable value, the overvoltage impact of the whole pump station must be considered

(2) the change of time parameters should be approved by the relevant professional departments

figure

(3) during the inspection process, some ranges can be expanded, such as the control of power units or the condition of capacitors

(III) undervoltage fault

1 Fault phenomenon

the frequency converter suddenly stops running, and the screen shows "we the electric voltage" or no display on the black screen

2. Fault inspection process

see figure for fault inspection process

3. Precautions for fault inspection

(1) pay attention to whether the three-phase incoming line of the power unit, which only plays a guiding role, is loose and intact

(2) generally, the maximum negative fluctuation value of inverter input power supply voltage is -35% ~ -40%

(3) the adjustment of technical data should be agreed by the relevant professional departments

(IV) 380V power failure

1 Fault phenomenon

the frequency converter suddenly stops running, the cooling fan stops working, and the display screen does not display

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) similar situations may occur during power switching, which should be noted during operation

(2) if UPS is installed, tripping caused by electrical abnormality can be eliminated in a short time

(3) pay attention to operation safety when checking whether there is power supply

(V) transformer overtemperature fault

1 Fault phenomenon

the converter trips due to the fault of high transformer temperature, stops running, and the display shows that the transformer temperature is very high

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) secondary isolation and safety measures shall be taken during inspection

(2) when measuring the actual temperature, keep a certain distance to prevent scalding

(3) when adjusting the thermal switch, pay attention to the conversion between Fahrenheit (℉) and Celsius (℃)

conversion formula: (℉) = 9/5 (℃) + 32

(VI) input power phase failure

1 The fault phenomenon

detection shows that the voltage, current, speed and vibration are abnormal, the motor sound is abnormal, and the frequency converter stops after running for 2 minutes

2. Fault inspection process

see figure for fault inspection process. Chongqing Big lathe processing plant

3 Precautions for fault inspection

(1) secondary isolation and safety measures shall be taken before inspection

(2) when checking car type equipment, it should be carried out in strict accordance with the operating procedures

(3) pay close attention to live parts and movable copies in the cabinet

(4) the replacement of contactor vacuum tank should be three-phase synchronous, and it is best to ask professionals to check and replace

(VII) ground fault

1 Fault phenomenon

the grounding protection relay alarms, the tripping signal acts, the contactor or circuit breaker trips, and the frequency converter stops running (the voltage loss fault is displayed on the frequency converter display)

2. Fault inspection process

see figure for fault inspection process

figure

figure

3 Precautions for fault inspection

(1) pull the trolley out of the cabinet before inspection

(2) when checking the insulation resistance to ground with a megger, disconnect the wire at the output end of the transformer or the input end of the frequency converter and hang it in the air. If the connecting wire is not disconnected, the frequency converter components will be damaged

(3) replace the damaged parts with the same model, specification and capacity, and check the qualified spare parts

(VIII) overcurrent fault

1 Fault phenomenon

overcurrent relay protection action, contactor or circuit breaker trip, frequency converter stops running, and the display shows voltage loss fault

2. Fault inspection process

the fault inspection process is shown in the figure. The output of H3PO4 iron Li is 57000 tons

figure

3 Precautions for fault inspection

(1) for the inspection of insulation support, special attention should be paid to the surface cracks and insulation breakdown, which are used in the automotive, electrical and electronic industries

(2) whether there is spider and dust scaling on the interphase conductors and support terminals

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