# Compressor trips breaker



## Mike335 (Sep 5, 2018)

I have a Craftsman 921153101 1HP 3-gallon oil-lubricated compressor from Home Depot that's a few years old. It filled the tank normally yesterday but made an unusual sound when the tank reached capacity and the motor shut off. It would not start up again when the air pressure dropped, and I found that the 20-amp breaker on the circuit had tripped. When I reset the breaker and attempt to restart the compressor, there is a spark at the front of the motor in or near the points and the breaker again trips. No hum, nothing but the spark and breaker trip. The motor has sufficient oil and turns freely along with the piston. The points on the centrifugal switch appear to be open and somewhat burned. Attempting to restart the motor with the tank empty causes a spark at the points and an immediate breaker trip. I'm guessing the motor, centrifugal switch, or the start capacitor are causing the overload/short. I haven't found a part number for the centrifugal switch which may not be sold separately. Photos are attached. Any guidance or advice would be much appreciated.


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## StevenHill (Feb 21, 2018)

Sounds to me that it is the centrifugal switchgrass that is the problem, you could take it off and take to your nearest motor rewind place and they would be able to get one, usually if the capacitors go you will see them split or with a bubble on it, you can test capacitors out with a decent multimeter


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## Mike335 (Sep 5, 2018)

StevenHill said:


> Sounds to me that it is the centrifugal switchgrass that is the problem, you could take it off and take to your nearest motor rewind place and they would be able to get one, usually if the capacitors go you will see them split or with a bubble on it, you can test capacitors out with a decent multimeter


Thanks Steven. I have a cheap digital multimeter. I don't know what to test for, resistance? The capacitors look like new, no swelling or leakage. It would be nice to fix this tool, seems like it should have plenty of life left, but I'm not finding much info online that pertains to the 921153101 model with these symptoms.


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