View Full Version : VSD motor fault

09-05-2013, 08:23 PM
Hi guys, I need to pick your brains. I had a VSD short to earth which took out the capacitor bank and some other components on the drive. ABB came in and repaired the drive but the motor failed to run. The motor is 250kw. The engineer asked us to wire in a temporary motor (30kw) to prove the drive was running ok. He operated the drive via a laptop thereby bypassing the compressor controller (this was to eliminate any possibility of the Elektonikon causing the problem) and the motor ran up ok. So the engineer is 99% certain the drive`s ok. We`ve pulled the motor back to try and run it with no load. The fault showing on the drive controller is "Motor phase" all the phases are ok with new fuses and the motor meggers out ok too. Now here`s my question: is there any other test we can do before we pull the motor out. Thanks in advance guys.

install monkey
09-05-2013, 08:36 PM
have u checked the isolator?

10-05-2013, 12:03 AM
Hi Glenn this http://www.refrigeration-engineer.com/forums/showthread.php?39037-Useful-Electric-Motor-Diagnostics-Book-Fluke should help with testing. There is a specialist motor tester out there - very expensive just to hire like $1000 plus. The motor specialists offered on a job last year so we ended up not using the tester and replaced the drive then the motor.

11-05-2013, 12:33 AM
Thanks tesla. I`m just looking at it now, lots of info there.

11-05-2013, 06:16 AM
hi,glenn,What is the internal protection of the motor? I think the problem is related to the motor. If motor has any problem, vfd will detect it. provide the all specification of vfd and motor.


13-05-2013, 12:57 AM
Hi moideen,
It`s protected by thermistors. I`m beginning to suspect there may be a broken winding/cable in the motor but it shows continuity on all the windings and cable from the drive to motor. Could there be enough undamaged cable to allow continuity but not enough the prevent the drive from detecting a missing phase as it doesn`t even attempt to turn before tripping.

13-05-2013, 04:41 PM
You must check isolation on motor, then you must verify if programming of the VSD is original from Atlas Copco if some components from it was changed, memory in special or it is possible to move memory from defective one to new one or same parameters programmed in new one.

16-05-2013, 05:15 AM