Captain
My question can actually apply to any generator really but it was a 12KW NEXUS controlled Honeywell branded unit I was looking at. The unit was going out immediately on under voltage.

In the end, found both the rotor and stator windings shorted to ground. Stator was additionally shorted between windings. I would give more details but find myself out of town without the notes but I don’t think it really impacts my question. Just to be clear, the meter readings were taken with brushes out, and all wiring disconnected from there respective connections going to the stator.

So my question has to do with the stator readings. The windings to ground are in the Mega Ohms, between 20 and 30. When the reading is taken, you can see the resistance climbing between those levels.

Frankly, I have not seen this before and am wondering what could have happened to have this high of a resistance reading and why are the numbers climbing like this?

Thanks in advance for any responses.
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78buckshot
How long had it been since the genny ran OK? My thought is the windings might have a lot of moisture in them or condensation within the can which could be the reason for the high readings. Do you remember the findings for the rotor? Certainly any short to ground is an instant red flag but I wonder if drying the stator would change your readings.
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Captain
No, unit was not wet, with those high resistance readings the windings for all intensive purposes are open. Going to simply replace the assembly.

what I was wondering though is if anyone else has experienced this using there DMM on windings.

thanks for the input
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Peddler
You really can't get good readings with a normal DMM temperature can change the readings dramatically, but anything to ground is no good or open is a problem. You need a Megger to fully test a stator.
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