Motor winding resistance value
The reactance (X r) of the motor will also ‘0’ at DC. As input is DC so there will be no induced voltage in the rotor and no current will move in the DC.
With due respect, I am doubtful it is a motor per your description ". RE: Resistance of small AC motor windings itsmoked (Electrical) 22 Apr 20 20:30ġ. Motor off and manually hold centrifugal switch openĭoes that make sense? Looking for any input before testing again since I don't want to needlessly burn up the start winding if something is obviously wrong. I'm confused by what I found because I thought the start winding should have higher resistance than the run windings?
I decided before trying again on a non-GFCI outlet to try to check the winding resistance, which is obviously something I should have done previously. Got lazy and decided to try again but same results. I took everything apart again and didn't see any burn marks or other damage. Their was a visible spark internal to the motor when the GFCI tripped. When I powered the motor (no load), it started immediately but tripped the GFCI quickly, two seconds at most. The available outlet is GFCI which well may be part of the issue. Hi speed = 115 volt, common = neutral, lo speed = no connection. Reassembled the motor and wired it to a plug and cord so I could bench test it before reinstalling. Switch seems to manually operate ok but I suspect springs are weak because of how old it is. Centrifugal switch was dirty but contacts were not welded. It was extremely dirty so I cleaned it up. I removed the motor and found there is no start capacitor. I realize I can replace motor pretty cheaply but wanted to try to fix this one. I thought perhaps bad start capacitor or bad centrifugal switch. When trying to start, it was just humming, but would start and run fine if the fan was spun manually. I have an old AO Smith 115 volt, 1/3 horsepower, two speed (1725/1140 rpm) motor from a belt driven fan.