Failing condenser fan motors.

**barriehie** · 07-10-2008, 02:09 AM

Most of the time when the cfm fails it's not running when I arrive and the repair is simple enough. Sometimes though the unit has been shut off and I can hope it fails while I'm there or get an amp meter reading high enough to indicate failure is imminent. So the question is there a percentage of rated amps that above which you can consider the motor faulty?

I've been amping the new ones after install and they run real close to 68% of what's on the motor plate. I had one that was running at .9 amps and the plate stated 1.1 amps, which is 82%. This motor failed while I was standing there after it had been running about 20 minutes. Amps shot up to 2.6 and it screached to a halt.

I know this is a broad question concerning different mfg.'s but since the motors are all made pretty much the same way they should fail about the same way.

TIA,
Barrie

**ddog1** · 07-10-2008, 03:32 AM

Hey... your percentage is about right for oem motors. Keep in mind that poorly position fan blades in relation to the shroud can cause high amps ..."chopping".... Also improper run caps even if they check out on mfd check doesnt always mean capacitants are performing in high temps, when in doubt change that 2 dollar part. Even fla is bad on a been static for a while unit. An option you have as a busy service tech who is waiting and waiting for a questionable fan motor too fail is to remove power and wait for blades to stop then apply power for 10 sec then remove power again repeating these steps 3-5 times. If you have bad windings, or run cap that motor will usually fail. If bearings are bad you will know also.
Hope this helps.