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View Full Version : Capacitor size change for blower motor


thumbs
Apr 11, 2007, 12:21 AM
general electric motor, direct drive, 5uf cap

First check:
when heat exchanger reached temp, the relay clicked but the blower fan just hummed.
The bearings seem OK as a slight push causes a rotation that continues for some time.
Also, such a slight push causes it to run fine for the cycle.

I pulled the blower, vacuumed the dust and oiled both plugged bearings. The fan rotated very freely with a slight flick. Mechanically it seems fine.

I replaced the 5uf capacitor with a new one of same value and it self-started several times, though it did seem a little labored.

The next day, it was back to just humming on 'start'.

I replaced the capacitor with a 10uf size and noticed a much stronger start 'grunt' and this seems to be doing OK.

Will replacing the original 5uf with a 10uf cause issues, dangers?

Since the bearings seem to be freewheeling just fine which indicates to me little friction, what else could be causing the hard starting?

JackT
Apr 11, 2007, 03:03 AM
Can you move the motor shaft sideways at all? It sounds to me like you have a bad bearing in your motor. I don't recommend increasing the capacitor up to a 10 mfd. This is just a temporary repair and won't last and could also cause it to over heat. If you have a amperage meter you need to check to see what you are drawing and compare it to the motor rating.

thumbs
Apr 15, 2007, 01:28 AM
Can you move the motor shaft sideways at all? It sounds to me like you have a bad bearing in your motor. I don't recommend increasing the capacitor up to a 10 mfd. This is just a temporary repair and won't last and could also cause it to over heat. If you have a amperage meter you need to check to see what you are drawing and compare it to the motor rating.

The shaft moves sideways slightly, but no more than a new motor.

Don't have an ac ammeter to test that.. guess another item for my wishlist.