re-purposed electric motor

Saws, Sanders, Drill Press etc. nice to have -- must have
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peter havriluk
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Joined: Sun Jul 29, 2012 12:30 pm
Location: Granby, CT

re-purposed electric motor

Post by peter havriluk » Thu Mar 23, 2017 9:53 am

I know virtually nothing about electric motors. I have a new-but-flawed 1/3 horsepower electric motor removed from a new Dayton whole-house fan when the motor, on low speed windings, never got up to speed and dimmed the house lights when turned on. But using the high-speed windings the motor seemed to work well. So...is this motor useful for powering anything I could use in guitar-making? Like a buffer? Any idea whether the motor warrants a trip to a motor repair shop to resolve the low-speed windings?

Thanks very much for any comments/insight/advice.
Peter Havriluk

John Parchem
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Re: re-purposed electric motor

Post by John Parchem » Thu Mar 23, 2017 10:23 am

A third of a hp is on the lowside for a buffer. As for the dimming, a motor windings start out as nearly a dead short to the AC power, Once the motor starts spinning it produces a back EMF (the motor acts as a generator when turning) that limits the current. So if the motor does not turn fast enough to limit the current into the windings you will get the lights dimming that you see or preferably a blown breaker. A lot of the motors have starters that limit the current while ramping up the RPMs, it could be that there is a problem with the motor on the low speed winding; it never gets started. I have had fans that act this way, spinning the fan by hand would start the motor spinning at the correct RPM.

ken cierp
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Re: re-purposed electric motor

Post by ken cierp » Thu Mar 23, 2017 10:36 am

A 1/3 hp is on the low end for a buffer but with the correct pulley arrangement it will work. Motors that size are a dime a dozen new and at just about any garage sale. $.02

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