Powertran VFD problem

[EddyCurrent]

Phill,
Unplug the machine from the mains first and wait 5 minutes for the capacitors to discharge, then disconnect the spindle cable right at the VFD. Get a multimeter set on a low ohms range and if the wires can be called A,B,C then test the resistance between A-B, A-C, B-C. you should get the same reading for all 3 tests and from what I've read lately it will be round about 4 ohms. If the tests are good then that eliminates the wiring to the spindle, the connector on the spindle, the spindle motor itself. I had a quick look on the Internet for a copy of your manual but could not find one, do you have a link to it ?
The problem might lie inside the inverter and these days they are not designed with user repair in mind. The VFD I use remains in fault until a manual reset has occurred so look in your manual for a fault reset sequence, it may be that the connector you found loose is giving an intermittent connection which you have now fixed.

This might be useful, by the sounds of it your drive should be okay up to what they call in this document the 'inverter circuit' and I'm guessing the input of yours is probably single phase. The principle is the same though, rectified AC in to make a DC supply which is then chopped up by the inverter circuit to produce a 3 phase AC output. So you should start on page 5.
http://www.newark.com/pdfs/techartic...hootingVFD.pdf