Yea, a participant! Thanks for checking in. You do understand I'm talking about a problem that has since been fixed, right? It was actually about a year ago. This was an intriguing problem for me, and no one I talked to had ever heard of it happening. A once-in-a-career thing.

I like your train of thought. Yes, I had tried wiring the motor directly to the mainline disconnect. When I turned it on, the fuses in the disconnect blew immediately. The fuses were the correct type for motor rated duty, and the correct amperage, etc, per the NEC. I'll go ahead and tell you that it had nothing to do with the problem. The 3 phase supply in the disconnect was of the proper voltage and phasing. The power supplied was proper in every way, and had nothing to do with the problem. But yes, I sure did a lot of checking on the power, during the course of this issue..lots of head scratching...

Just as an aside, it was interesting that fuses of the same rating DID NOT blow while the power was going through the Seimens solid state starter. Its' current limiting abilities acted like a safety valve. It would allow a certain steady state of current, hundreds of amps even, depending on what allowable percentage of FLA you set in the parameters, but no more than that. But this also had nothing to do with the problem, I thought it was just interesting.

What would you do next?


(oh, boy, got one on the "hook"!) :^)