919.167312 compressor starts then trips breaker
by Craig Kovarik
(Brighton, MI, USA)
Hello. I have a Craftsman 919.167312, 30 gal, 2Hp, 6Hp peak, air compressor with a AO Smith Z-D26712 115 VAC motor. Build date of 10-22-03.
With no pressure in the tank, when it is switched on, the motor will run for 2-3 seconds then trip the breaker.
I checked the run capacitor with an analog meter and saw a "good" response (I will test with a multimeter tomorrow at work to determine the capacitance).
I removed the fan, disconnected the pump and removed the eccentric counterweight so that there is no external load on the motor and the result was the same failure.
I then removed the cover to the switch and connected the wires directly to that the motor was powered directly when the cord was plugged into an outlet. This would eliminate the pressure switch from the circuit.
Again, the same failure mode... runs for 2-3 seconds and trips the breaker.
If I try to run it again quickly after the first failure it will run for 1-2 seconds before the second failure.
I have not yet removed the motor cover to examine the start capacitor (I understand that there is a start capacitor under the motor end cover).
In your opinion is there anything else I can test for besides the capacitor and inspection of the centrifugal switch?
Have you heard of this type of failure before and found a resolution?
I have seen a couple threads with similar challenges but haven't read of any successful reworks ... yet!!!