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MN Renovator · 10-28-14, 01:23 PM

Could be just the capacitor, I've had that happen once on the fan for an outdoor condenser and it just hummed and slowly very turned but eventually it would speed up enough to spin up to a normal speed.

Two years ago on the hottest day of July the compressor wouldn't fire up and popped the breaker. I ohmed the windings against the case and it wasn't shorted to ground and so I checked the resistance between each winding connection and everything checked out so I replaced the capacitor and once it was out I realized it was soaked in oil.

My personal checklist is: 1. Check if the motor spins freely and without bearing noise. 2. Ohm case to windings to check for a short. 3. Make sure all connections are clean and connected firmly. 4. Try another speed tap if there are others. If this is still failing, I usually remove the motor and wire power directly rather than through the appliance.

If everything checks out and it is a PSC motor, I replace the cap. If it is not a perm-lubed motor and I can oil it, I'll oil the motor.

A personal note, I once had a motor that ran fine and would eventually get hot and slow down. Turns out it was shorted to ground and I forgot to check. I pulled the blower from the cabinet and while supporting the blower housing with one hand I hit the door safety switch with the other hand and felt a surprise. Be sure to have a ground attached when playing with motors.

Standard disclaimer - Don't mess with motors or electricity unless you know how to not get injured or killed. Getting caught in fan blades, burned, etc. can result in a bad day.

10-28-14, 01:23 PM	#5
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Could be just the capacitor, I've had that happen once on the fan for an outdoor condenser and it just hummed and slowly very turned but eventually it would speed up enough to spin up to a normal speed. Two years ago on the hottest day of July the compressor wouldn't fire up and popped the breaker. I ohmed the windings against the case and it wasn't shorted to ground and so I checked the resistance between each winding connection and everything checked out so I replaced the capacitor and once it was out I realized it was soaked in oil. My personal checklist is: 1. Check if the motor spins freely and without bearing noise. 2. Ohm case to windings to check for a short. 3. Make sure all connections are clean and connected firmly. 4. Try another speed tap if there are others. If this is still failing, I usually remove the motor and wire power directly rather than through the appliance. If everything checks out and it is a PSC motor, I replace the cap. If it is not a perm-lubed motor and I can oil it, I'll oil the motor. A personal note, I once had a motor that ran fine and would eventually get hot and slow down. Turns out it was shorted to ground and I forgot to check. I pulled the blower from the cabinet and while supporting the blower housing with one hand I hit the door safety switch with the other hand and felt a surprise. Be sure to have a ground attached when playing with motors. Standard disclaimer - Don't mess with motors or electricity unless you know how to not get injured or killed. Getting caught in fan blades, burned, etc. can result in a bad day. Last edited by MN Renovator; 10-28-14 at 01:27 PM..