Analysis of 15 causes of overcurrent failure of the inverter

- Aug 01, 2019-

The following is basically the cause of all possible inverter overcurrents, the specific repair fault point stoist to combine the actual process, equipment and environmental situation analysis on site.

1. Sudden load change or blocking; check the load, motor current and mechanical part of the system when the drive is repaired,

2. Close the output contactor, if the output contactor is used, the modulation of the drive should be stopped before the contactor is disconnected.

3. The motor connection is wrong; check the motor voltage on the motor nameplate and the connection method, and compare it with the 99 sets of parameters.

4. Too short slope time, so that the drive service overcurrent controller does not have enough control time;

5. The cause of the drive repair overcurrent is the motor speed or torque oscillation; Torque given cause: Check whether the torque given oscillates. Caused by overcompensation for speed response: check the parameter settings of the speed regulator. Caused by excessive feedback filtering time. Caused by the wrong pulse encoder value: check the pulse encoder's waveform and check the number of pulses.

6. Caused by motor model: get the correct motor data from the motor nameplate and compare 99 sets of parameters.Output short circuit: damaged motor cable or motor.When the drive repair to check the motor and motor wire insulation and power substation cable and the connection between the drive, in the standard mode to run the inverter, if the drive does not trip, it means that the drive is good.

7. The output ground fault in the ground ingress power grid, check and measure the motor and motor cable with a high resistance meter or insulation meter.

8. Wrong motor and transmission selection, check whether the motor rating current value is in what state.Check the output current, torque, and limit words.

9. Power factor correction capacitor and surge absorber, the drive repair to confirm that there are no power factor correction capacitors and surge absorbers on the motor cable.

10. Pulse encoder connection, check pulse encoder, pulse encoder wiring (including phase sequence) and XTAC module.

11. Incorrect motor data, check and correct motor data according to motor nameplate.

12. Incorrect inverter type, inverter repair to compare the transmission of the nameplate and software parameters.

13. No communication between rmIO board and RINT/AINT and AGDR boards, check and replace fiber and check flat wires.

14. Overcurrent in standard control mode, check and replace the current transformer, check the output current, torque and limit words.

15. The drive servicer is faulty, check and replace the current sensor, replace the XINT plate, confirm that the flat cable is properly connected, and replace all fibers between the INTS plate and the XPBU board. (in the case of parallel connections)