A/C condenser fan not working

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Old 09-06-15, 09:23 AM
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Exclamation A/C condenser fan not working

I have a 2 and a half ton air conditioner and I noticed the yesterday that the condenser fan was just humming. I turned it off for about an hour and turned it back on and it worked for about 30 minutes. I thought that it just got hot and cooled off enough that it started to work again. But today I checked the capacitor and I think it is fine but now when I turn the outside breaker back on the fan hums. Even though I don't have the thermostat turn on the fan hums and the compressor doesn't come on. The compressor comes on if I push the contact in but the fan still hums. The only way to get it to stop is to flip the breaker outside. I have turned to fan blades and the motor seems to be ok.

Any help would be wonderful.
 
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Old 09-06-15, 09:33 AM
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Welcome to the forums.

It sounds like the condensor fan motor has a shorted winding to ground. That shorted winding will keep power to the motor all the time, even with the contactor open, since only one leg of the main power is being disconnected.

You'll need to disconnect the fan motor wires and check each one to ground. Use a high ohms scale if using an analog meter. If digital.... use auto. position.
 
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Old 09-06-15, 10:27 AM
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I checked the wiring but didn't find any problems. I did find that a few of the wires were nicked and I put tape on them but I still have the same problem. Now the motor will spin but not very fast.
 
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