Failure analysis of Mitsubishi Frequency Converter OC1 and OC3

Many times when Mitsubishi frequency converter presents OC (overcurrent problem), it is caused by the following reasons. Take A500 series frequency converter as an example:

1) Caused by improper parameter setting, such as too short time setting.

2). Caused by external factors, such as motor winding short circuit, including interphase short circuit, short circuit to the ground, etc.

3) Inverter hardware faults, such as Hall sensor damage, IGBT module damage, etc.

In maintenance, sometimes excluded these reasons may still be to solve the problem, OC fault still exists, of course, the replacement of the control board is not the solution to the problem, then we can consider whether there is a problem in the drive circuit. The detection circuit of Mitsubishi A500 inverter is quite powerful. As long as there is a problem at any of the above detection points, it may alarm and fail to operate normally. In addition to the general drive circuit includes the drive power supply, drive optocoupler isolation, drive signal method circuit, but also includes the output signal feedback circuit. The detection direction primarily includes several components of the Mitsubishi drive circuit.