Do you need to disconnect VFD for Megger test?

Do you need to disconnect VFD for Megger test?

Sorry, but you need to disconnect the VFD before carrying out a megger test on the motor. If you need to do this regularly, consider installing a set of removable links on the drive output cabling or, if the motor is not too large, possibly a lockable disconnect switch between the VFD and motor.

What do you need to know about the Megger test?

Isolation. It's the motor that you are interested to test not the drive. Megger test line-line-ground leak, its an insulation test. Connecting the drive and the motor, you will have 2 parallel networks and you can not tell which is giving the test reading anomaly.

Can you test with VFD or softstarter connected?

This question is repeated by many but there is no conclusive answer, some say we have to disconnect, some say we can carryout test without disconnection Testing motor insulation with VFD / Softstarter connected will lead to damage the Thyrister or SCR , is there any way we can overcome this problem and continue to test motor without disconnection.