Air Conditioning - Home A/C fan motor stops after 15 minutes
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johnm
05-09-06, 08:00 PM
OK guys, maybe I can find some help here before I completely bald from pulling my hair out.
I live in florida, central air unit outside with blower furnace inside garage. I had a bearing go bad in the outsdie unit for the fan. Went and purchased a 1/4 horse 208v single phase GE motor. Couldn't read the old motor, label was wiped out.
removed old motor and noticed it had 3 leads to it, black, yellow, brown. So my guess is the original was a 2 phase motor to begin with. Put my meter on the naked wires and found 2 with 237v AC. Black and yellow. Wire nutted the third (brown). BTW the 3rd (brown) also provided 237v when using it with the black wire. Ok so I looked at the wiring diagram on the new motor, wired it for 208v and connected the yellow to the high side and black to low. Connected a ground to case and the unit, set it on a cardboard box next to the unit and fired it up. Ran perfectly including correct rotation CW. Put it in the unit ouside and it runs for 10-15 minutes and shuts off, but the compressor keeps running, the blower in the furnace or air handler? in the garage keeps running.
The motor does not feel hot, except for general warmth of the hot air pulled off the condensor coils, hot surrounding air.
I've read a couple posts here, should I be looking for a faulty relay somewhere? I'm not sure this would be the problem, because the old motor would just continue to hum locked up well after 15 minutes..
Any help here would be greatly appriciated.
the motor I purchased is a 120/208v GE part number p250
I live in florida, central air unit outside with blower furnace inside garage. I had a bearing go bad in the outsdie unit for the fan. Went and purchased a 1/4 horse 208v single phase GE motor. Couldn't read the old motor, label was wiped out.
removed old motor and noticed it had 3 leads to it, black, yellow, brown. So my guess is the original was a 2 phase motor to begin with. Put my meter on the naked wires and found 2 with 237v AC. Black and yellow. Wire nutted the third (brown). BTW the 3rd (brown) also provided 237v when using it with the black wire. Ok so I looked at the wiring diagram on the new motor, wired it for 208v and connected the yellow to the high side and black to low. Connected a ground to case and the unit, set it on a cardboard box next to the unit and fired it up. Ran perfectly including correct rotation CW. Put it in the unit ouside and it runs for 10-15 minutes and shuts off, but the compressor keeps running, the blower in the furnace or air handler? in the garage keeps running.
The motor does not feel hot, except for general warmth of the hot air pulled off the condensor coils, hot surrounding air.
I've read a couple posts here, should I be looking for a faulty relay somewhere? I'm not sure this would be the problem, because the old motor would just continue to hum locked up well after 15 minutes..
Any help here would be greatly appriciated.
the motor I purchased is a 120/208v GE part number p250
johnm
05-09-06, 08:58 PM
OK I was able to read the original motor and it says single phase.
So maybe I have it wired wrong. Meaning that I have 120 into the motor which is expecting 208v because of the way I read the label.
can someone just answer this for me.
Single phase = 1 hot and 1 neutral? at 120v
Single phase = 2 hot and 1 neutral at 208v
But if the wiring diagram on the motor only has 2 inputs for both 120 and 208v, then do you provide both hots into 1 input and then the neutral to the other for 208v? This is the cofusing part for me since the original motor had 3 wires, and this one only directs me to connect to 2 for both 120v and 208v.
Another question, if I am on the right track here, would wiring it for 120 when it expects 208 cause it to shut down after 10-15 minutes due to a current draw heating up the thermal protection?
Any professional insight would be helpful. I'm not asking for your help in burning down my house, just if I am on the right track.
Thanks
John
So maybe I have it wired wrong. Meaning that I have 120 into the motor which is expecting 208v because of the way I read the label.
can someone just answer this for me.
Single phase = 1 hot and 1 neutral? at 120v
Single phase = 2 hot and 1 neutral at 208v
But if the wiring diagram on the motor only has 2 inputs for both 120 and 208v, then do you provide both hots into 1 input and then the neutral to the other for 208v? This is the cofusing part for me since the original motor had 3 wires, and this one only directs me to connect to 2 for both 120v and 208v.
Another question, if I am on the right track here, would wiring it for 120 when it expects 208 cause it to shut down after 10-15 minutes due to a current draw heating up the thermal protection?
Any professional insight would be helpful. I'm not asking for your help in burning down my house, just if I am on the right track.
Thanks
John