Have an issue with A/C tripping the circuit breaker
I am an Electronics Technician, 25 yrs. Used to be a construction electrician before that. But no A/C experience, and motors are kind of a weak point for me.
I narrowed the problem to the outside unit. When I switch on the disconnect switch, the motor turns a little bit with a kind of growling noise, then the breaker in the house trips. What is interesting is the A/C is turned off at the thermostat, so the fan should not be coming on.
I opened up the unit and don't see anything imediately obvious like bug problems, cut and shorted wires etc. I removed the feeder wires, turned on the breaker and disconnect switch and all ok, so I am sure the problem is with the outside unit.
Model number is XXXXX Serial number is XXXXX This is a Heat Pump, but is not being used as such.
I did observe the contactor switch when I threw the disconnect on, and it did not engage. So why is the motor trying to turn on?
Looking for technical advice as to what I should look at or measure next.