1. Fault Occurrence and Handling Due to a sudden burst water pipe, water sprayed into the brake cabinet of a running gypsum centrifuge (containing the braking unit and braking resistor). This caused the Me switch on the incoming voltage line to trip, tripping all equipment in that section. Because of the cascading trip, a large current was clearly generated at the time of the fault, causing the Me switch to trip instantly. After a detailed inspection, it was confirmed that the power cable was not grounded or short-circuited. The motor was also normal. Therefore, a spare inverter was installed. Power was restored for testing. After power was restored, the low-voltage incoming Me switch did not trip, but the charging indicator lights on the inverter and braking unit did not illuminate. The keypad panel also showed no display, and the equipment still could not operate normally. Since the charging indicator lights were not lit, it was determined that the keypad panel was not damaged, and the problem lay with the spare inverter. The original inverter was replaced, and power was restored for observation. The moment the inverter received power, the incoming Me switch tripped again. Clearly, there was a serious short circuit in the main circuit inside this inverter. While replacing the inverter... Considering the water was sprayed directly into the brake cabinet, the brake unit and brake resistor were the focus of the inspection. The inspection revealed that the brake resistor value was normal, but the resistance between the DB and N terminals of the brake unit was only a few ohms. Due to oversight, the brake unit was not opened for further inspection. Now both inverters are faulty. To restore production as quickly as possible, we opened both inverters overnight for inspection. The first inverter was more severely damaged. Upon opening the front cover, slight arcing marks were immediately found between the incoming busbars. The insulation between the three phases and between the phase and ground was normal. Further inspection after removing the control board revealed blackened marks on the surface of both resistors. Resistance measurements showed the resistors were damaged, and upon removal, traces of ground discharge were found on the back of the resistors. After further inspection and confirmation that the diodes, IGBTs, and other components were normal, the resistors were replaced. The busbars were also repaired. Upon opening the second inverter, only resistor R was found to be burnt out, so it was replaced. [b][align=center]For more details, please click: Analysis of Inverter Faults in Gypsum Centrifuge[/align][/b]