# Troubleshooting VFD



## jtashaffer (Sep 8, 2010)

The VFD is a square D altivar 58. It would give a overbreaking fault and a short circuit fault at different times. I check the vibe motors, wiring and more. All checked good, it would run a couple of hours then kick out for one of those to faults. Wanted to see if anyone had any Ideas of what was wrong.


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## MDShunk (Jan 7, 2007)

Both of those faults are very typical of a failed or failing motor. 

My troubleshooting procedure would start with disconnecting the branch circuit conductors from the drive and and the peckerhead of the motor, and megger each conductor to each other and to the pipe. If that proved okay, I'd megger each conductor of the motor's peckerhead to the steel of the motor. Check winding resistance and confirm they're all the same. Perform PI and DAR tests, if you can. 

Even from far away, I feel pretty good about saying that if your branch circuit conductors megger fine, replacing the motor will solve your problem. Why do I think that? History shows me that a VFD is an excellent troubleshooting tool all on it's own. Very damned rarely do they "lie" to you with respect to the fault they're giving. You say "all checked good", but I really think you're wrong about that. You have a motor problem.


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## Jlarson (Jun 28, 2009)

Yeah just like MD said, it's probably the motor.


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