A/C outside fan slow and compressor trips breaker

Old 07-24-09, 02:44 PM
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Thumbs down A/C outside fan slow and compressor trips breaker

Gibson package unit. Outside squirrel cage blower fan hums, will spin slower than normal when started by hand. I assume a capacitor is bad.
Is this correct?

When I switch on the compressor the breaker trips after a few seconds. Not sure about the evaporator fan. Power goes off to fast.

I have installed a new main panel breaker and a new contactor with the same results. I have switched out the sub panel breakers (breaker still trips when compressor is turned on) Power supply seems good.

I swapped heater power supply wires from sub panel to unit with the same results.
Not sure if compressor is fried or what.

I think I see three capacitors on this thing.

Should I replace the blower and the compressor caps?

Can you help give me some ideas to try.
Old 07-24-09, 04:42 PM
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What is the voltage going to the unit? You'll need to test the compressor motor for a grounded winding. Scratch a clean place on the larger tube going to the compressor. Make a sketch of the wires where they connect to the compressor teminals. Remove the wires and one at a time ohms test each pin [on the compressor] to the clean place on the tube. If you get a reading the compressor motor is grounded.

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