Causes of repeated shutdowns after inverter reset

A piece of equipment in the workshop broke down. The leader asked the electrician to deal with it. After the electrician arrived at the site to check, he found that the inverter controlling the motor had stopped because of an alarm. A code was displayed on the inverter. After checking the manual, he found that it was an overcurrent.

After the electrician checked the motor and found no problems, he reset the inverter and restarted it. After a few minutes, the inverter alarmed and stopped again.

I reset the inverter again, took an ammeter, turned it on and measured the current, and found that the current was normal, but the inverter alarmed and stopped again.

The electrician had no choice but to ask the leader for instructions, saying that the inverter was broken and could not be repaired, and needed to be replaced with a new one. I didn't expect the leader to say that it was useless to ask you to replace a new one when you couldn't even fix a small problem.

The electrician was so angry that he didn't argue. Everyone was talking about what was wrong with the inverter. Should an electrician repair the inverter? Should he repair the inverter? What should he do if he encounters such a leader?

Electrician A: The motor has overcurrent and cannot be reset at will. The motor should be disconnected from the load and the motor bearing should be checked to see if it is in good condition. Then run it without load to see if there is overcurrent. If it is normal, the mechanical part should be checked.

Electrician B: As long as the electrician knows these, he can basically determine the problem. In fact, when an experienced electrician comes to repair, he will ask the operator some questions and then determine where the problem is. If it is a second-rate electrician, most of them cannot find the cause. The first thing they do is to say this should be replaced and that should be replaced. I am also an operator. When an experienced electrician comes to repair, I will take the initiative to tell him what happened during the operation.

Electrician C: If you cannot check whether it is the motor or the inverter that is overcurrent, try connecting the inverter to another identical motor. If overcurrent occurs again, it means that the inverter thermal protection is broken. The inverter is overcurrent and must be repaired or replaced with a new inverter. Otherwise, it is the motor that is overcurrent and the motor bearing is broken or stuck, causing overcurrent. Replacing the motor bearing can solve the problem. If you have checked and tried it yourself and found that it is indeed the inverter that is overcurrent, and your boss thinks it is a minor problem and does not repair it, you can only install another identical inverter. This solves the problem and proves that it is the inverter. The boss can take the disassembled unit and repair it or not. If it is repaired, restore it. If not, leave it there and see what the boss has to say.

Electrician D: Is it an instantaneous overcurrent or a constant overcurrent? Check the fault record of the current when the alarm is triggered. The motor insulation is more likely to have problems. The mechanical transmission resistance bearing has a lower chance of jamming, but that doesn't mean it doesn't exist. Finally, consider the performance of the inverter. If the problem persists after changing the inverter, refer to steps 1 and 2!