Compressor motor start winding resistance?

by Rick
(Hackensack, MN)

I have a US motors 7.5 hp single phase air compressor that after I moved to another house it trips the breaker immediately. The capacitors are within spec. When I bypass the capacitor on what I'm assuming is the start winding I have about 1.95 ohms. On the run winding I'm getting .85 ohms. I'm hoping that I didn't short out a winding when I moved it. Air compressor is a 1997 Campbell Hausfeld 80 gallon.

Comments for Compressor motor start winding resistance?

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Feb 25, 2017
start winding
by: Doug in

Not unreasonable.

What type and rating is the breaker?

What wire and how long from the breaker?

Feb 25, 2017
Motor tripping breaker
by: Buster

Hey Rick, if the motor was ok before the move, and starting tripping the circuit breaker after, I would suspect the supply to the motor first. That's a power hungry motor on startup and needs at least a 50 amp breaker and 8 gauge wire, maybe 10 gauge if it's close by. You didn't mention what size the breaker was that is tripping, just a thought.

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