Condenser Fan Motor Quirks

Old 08-10-02, 09:36 PM
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Condenser Fan Motor Quirks

My "future" father in law has a 22 year old RUND unit.
Yesterday, the cooling fan motor quit on him. I recommended to him to replace the fan motor and the capacitor.

He got the parts and I replaced the capacitor and the old fan started up fine. I had swapped in the new fan motor but it didnt work at all so I figured that it was bad out of the box. (Common????) However, the old fan motor ran like a champ - for about 6 hours then it went kaput. He went out to look at it and he felt the area where the fan motor was mounted and said that it had gotten warm.

After doing something else for about 3 hours we returned and turned down the thermostat and low and behold the outside kicked on. I dont know how long it will last this time. ITs hot here in Oklahoma and I hope that the ol codger will have some cool air this evening until I can get this resolved!

The condesor seems to be running just fine as when the whole unit is operating we get alot of nice cold air.

Could it be that the fan motor is overheating and shutting itself down? It is a 4 wire unit - recommend a replacement? Now the capacitor was changed as well - met all the requirements. Could that be bad too even though brand new? I have yet to clean the contacts on the relay but I dont think that would cause the fan to go out as it didnt work when I push it in manually.

Any help would greatly appreciated as you know how important it is to impress the in laws! Any help short of replacing the unit would be great! He just wants it to run for at least 6 months until he can afford to buy another unit and replace the whole deal.

Thanks again.
Old 08-10-02, 11:08 PM
lynn comstock
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I presume that the new fan capacitor is exactly the same micro-farad size as the old one. If not, that is a problem that will cause the motor to overheat.

Considering its age, I would think that the fan motor bearings are seizing up as the motor runs, causing the fan motor to overheat. It is clear that the fan motor protector is stopping the fan (to keep the fan motor from burning out). Then when it cools down, it resets and the motor will run again until it overheats.

Motor failures...out of the box...are RARE. How did it fail to work? Did it hum, buzz, move, smoke or do anything at all?
Old 08-10-02, 11:20 PM
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Yes, the cap was the same, but I will recheck it today.

The new motor didnt do anything - no hum, smoke or anything, just got a little warm. I forgot the brand begins with a PRO something.

But the original is 4 wire hook up and the new one is 5.
The new one had a brown,black,orange,purple,yellow

The black and the orange are to go to the line in on the contactor I know that, and the directions said for the yellow and brown to go to the cap with the purple to a line for voltage. It is a reversible fan so it said to switch the brown with the purple for clockwise rotation, however the older one is cclockwise.

The old one had two oranges, one brown and one black with the black to line, shorter of the two orange to line and the brown and longer orange to the cap.

The condesor powers up fine so I am not suspecting it, however I will resistance test it as well.
Old 08-11-02, 04:21 PM
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The new capacitor doesn't necessarily want to be the same as the the old one. It wants to be the size called for on the label of the new motor. 97 times out of 100, it's the same size but not always. Check the wiring label on the motor again. I think you have the brown or purple [whichever one you need for the correct rotation] on the wrong voltage phase. Iaaume the new motor is the right voltage, speed and horsepower?
Old 08-12-02, 09:55 AM
lynn comstock
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Your 4 wire motor was a 1 speed, 2 wires for power and 2 to the capacitor.

The 5 wire should have 2 power wires and 2 to the capacitor also. I believe the other wire may be for a second speed. The motor nameplate should answer this question. Only one of the speed wires should be connected to power. The other one should not be connected.

Another posibility is that the purple wire that you said goes to a power wire, needs to go to the OTHER power wire. If you can Email me a picture of the wiring diagram or instruction page, I could be more certain of what you have, Wire colors are not standardized enough to help.
Old 08-14-02, 05:44 PM
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Well, we had the fan tested and it was bad - right out of the box.

But, along with the fan motor, run capacitor and the condesor cap to be replaced, He decided to replace the whole unit so my job is finished!

I want to thank everyone for their emails, feedback and all around help!

Thanks a bunch!

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