3/4 horse electric motor - Sparks when started ???


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Old 07-14-14, 10:02 AM
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3/4 horse electric motor - Sparks when started ???

Hi All,

I was given a Shertech 3/4 horse electric motor that was pretty dirty but was supposed to be in good working order.

I stripped it down, cleaned it up and put it back together yesterday. When I flipped the switch the motor turns right on and spins with plenty of gusto. Although I did also notice that when I threw the switch there was a little spark from behind the electrical board. This board is 2 sided with all of the wire connections on the front, and a spring contact on the back. The spark seemed to be coming from the back side. This only happens when the motor is started from a dead stop. If I flip it on / off / on while the rotor is still turning I don't get this spark. Also, when I start it from a dead stop the lights in my garage dim a bit lol. In case it's useful, this motor does not have a start capacitor.

I know a little about electric motors but I don't know enough to call this normal / or if I should be concerned.

Any thoughts?
 
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Old 07-14-14, 10:20 AM
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Are you connecting to the correct voltage?
 
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Old 07-14-14, 02:20 PM
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Sounds like the centrifugal switch for the starting winding opening as the motor comes up to speed. Completely normal.
 
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Old 07-15-14, 09:19 AM
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Hi, these motor run off normal household 115v, and I'm testing them on a good 20 amp leg in my garage. I dont think that's the problem.


Thanks for the reply's.
 
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Old 07-15-14, 09:45 AM
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As Furd said, this is a normal event in the starting of this type of motor. The centrifugal switch is attached to the back of this circuit board, and the arc is from this centrifugal switch opening as the motor comes up to speed. It sounds like your motor is OK.
Andy
 
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Old 07-16-14, 09:20 AM
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Thanks guys, this makes me feel more confident about putting it into service.

Appreciate the replies.
 
 

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