Whole House Fan Sometimes Fails to Start

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Old 07-09-19, 02:46 PM
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Whole House Fan Sometimes Fails to Start

I have a whole house fan which I believe has a shaded pole motor, though it might be a permanent split capacitor motor.. There is a capacitor, but no centrifugal switch. It is a two speed motor,

Some times it starts up just fine, and other times I have to spin it to get it started. If it had a centrifugal switch, I would understand where to look. but I can't see where to start troubleshooting. Seems like it should either start or not, but it is intermittent.
 
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Old 07-09-19, 11:04 PM
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Most of those fan motors do have a centrifugal start switch. It's in the end bell of the motor opposite of the shaft end. You could try changing the capacitor.

Look on the motor for a wiring diagram. A start switch may be shown on that.
 
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Old 07-11-19, 01:34 AM
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I don't believe it has a centrifugal switch, but I will go a check again. Usually you can hear them click in as the motor starts.

I notice that if the fan does not start on it's own, it takes a long time to come up to speed if I spin it by hand. If it starts on its own, it only takes a few seconds to reach operating speed.
 
 

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