# 1 hp electric motor doesn't spin.



## Jim Bunton (Mar 16, 2004)

I am having a problem with my 1hp electric motor on my band saw. When I turn it on it hums like it is trying to start but doesn't spin. It blows the breaker if I leave it on more then about 30 seconds. Would this be bad brushes or some thing more serious? Any help would be appreciated.


Thank You 

Jim Bunton


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## Windy in Kansas (Jun 16, 2002)

Is it a capacitor start motor? If so I would guess the capacitor has gone bad. Watch out for nasty shocks if you mess with it.


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## deaconjim (Oct 31, 2005)

Unplug the saw and try to turn the motor by hand. If it turns properly, it could either be a start capacitor as Windy suggested. If it doesn't turn, something has it bound, either in the saw or the motor itself.


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## Jim Bunton (Mar 16, 2004)

thank you both for your quick responses. The motor and saw turn freely by hand so from what you have both said I will test the capacitor. Looking online it looks easy enough to test. I will be careful to discharge the capacitor before testing any thing else I should watch out for?

Jim


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## Caz (Jun 29, 2002)

It could also be a capacitive start, inductive run motor. If it is this type the capacitor could be good but the centrifigal switch (which closes when the motor stops and opens when it comes up to speed to allow the capacitor to start it) could have some dirt in it not allowing the contacts to close and put the capacitor back into the circuit for starting. John


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## Jim Bunton (Mar 16, 2004)

Caz, any easy way to check this switch? 

Jim


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## deaconjim (Oct 31, 2005)

The switch is probably inside the end of the motor (opposite end from the drive pulley). Pull the motor and remove the end cap. You can check the contacts with an ohm meter. If the are closed and not making good contact, pry them apart and clean them with some fine sandpaper and recheck with the ohm meter.


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## Jim Bunton (Mar 16, 2004)

Just to make sure I understand how this switch works. I am guessing they should be closed when the motor is unplugged. If tested and the ohm meter is reading an open switch then it is a switch problem. Is that correct?

Jim


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## deaconjim (Oct 31, 2005)

Jim Bunton said:


> Just to make sure I understand how this switch works. I am guessing they should be closed when the motor is unplugged. If tested and the ohm meter is reading an open switch then it is a switch problem. Is that correct?
> 
> Jim


Yes, the switch is closed until the motor is up to speed. When the motor is stopped, the contacts should be closed.


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## Ky-Jeeper (Sep 5, 2010)

110 or 220volt ?


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## Jim Bunton (Mar 16, 2004)

110 volt

Jim


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## Jim Bunton (Mar 16, 2004)

Thank you one and all for your help. I finally got back to the motor ( I needed the saw today). I checked the capacitor and it seemed like it tested good, so I went a little deeper to the switch it read open when I checked the wires. A couple of blasts of compressed air, and I am up and running. 

A grateful member of homesteading today

Jim Bunton


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