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View Full Version : AC Condenser Fan Motor Voltage Issue


Kirsten80
Jul 22, 2014, 09:25 AM
Hi!
I have a question about my Condenser Fan Motor. Our old fan motor started squealing and eventually locked up and we went to an HVAC supply place and bought a new fan motor and capacitor. We installed in late in the evening and it appeared to be working fine. However, during the heat of the day, the fan overheats and stops running, the compressor stays on though. If I turn it off for about ten minutes or mist it with water to cool it down, it will come back on and run for about ten or fifteen minutes before shutting down. Is this a problem with the run capacitor? The receipt says it's a 1/3-1/8 hp 825rpm motor with a 7.5 MFD 370V capacitor. Again, it only has problems during the heat of the day (90+ outside), at night in runs with no problem. Thanks in advance for any help you can give me!

smoothy
Jul 22, 2014, 09:41 AM
I assuming you don't have a lot of leaves, grass or other debris visibly blocking airflow in the coils?

Kirsten80
Jul 22, 2014, 09:48 AM
No, that was the first thing we checked and it appears to be pretty clean, we can see light shining through it just fine.

smoothy
Jul 22, 2014, 09:53 AM
Do you have a meter to measure voltage and know how to use it?

Kirsten80
Jul 22, 2014, 09:57 AM
No, but my dad is coming this afternoon to take a look and he's bringing one. I'm mainly wondering if the capacitor we got is the wrong size for this motor. We had no voltage issues with the old motor and capacitor so just trying to rule some things out.

bitters
Jul 22, 2014, 11:52 AM
No, but my dad is coming this afternoon to take a look and he's bringing one. I'm mainly wondering if the capacitor we got is the wrong size for this motor. We had no voltage issues with the old motor and capacitor so just trying to rule some things out.

Check to make sure the fan is blowing in the right direction. Should blow up from the unit. You might have put the blades on the wrong way. Check to see if the motor is reversible.

smoothy
Jul 22, 2014, 12:33 PM
You can't put the blades in the wrong way... if you flip them over (assuming you even can) they still blow the same direction. Try it some time, you will see what I mean.

bitters
Jul 22, 2014, 02:33 PM
Thanks smoothy, your right, you would have a hard time tighting the set screw.

ma0641
Jul 22, 2014, 05:20 PM
Sounds like a thermal overload it shutting off the motor to keep it from overheating. Misting it cools it down. If it is a 2 wire capacitor, it is only used for starting. Make sure the motor is wired the same as the old one, CW vs. CCW.

Kirsten80
Jul 23, 2014, 07:06 AM
Thank you everyone! Bitters, you turned out to be right. The motor has a switch that changed the direction that the fan was turning. I was feeling air coming up before, but once we reversed it, it was much stronger. It's been running for about 18 hours now with no problem. Thanks everyone for your input!