2hp motor hums and not turning

Gauthack

Jul 4, 2024
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I have a 2hp 120v/240v ( currently connected 120v) electric motor that will run when not under mechanical load for about 10 seconds then the overload trips. When under mechanical load it does not run, just hums for about 5 seconds then trips the over load.

I can turn the shaft freely with the belt to the load on or off.1000007677.jpg
 

dave9

Mar 5, 2017
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Is that a start/run capacitor hiding under that bulge I see on the side? If so then I'd check whether it's going bad.
 

roughshawd

Jul 13, 2020
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Jul 13, 2020
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I think my new phone has cooked windings too... but I will test the caps to be sure....
Note: this is a new phone.

yeah ! @73%(*$ motors are probably for recycling....

replace the motor and the capacitor starter... make sure all the specs are exact, and paint it hot red or green, draw a banana and peanut butter sandwich on it, and then sign it with "Elvis was here" to make it worth millions.
 
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73's de Edd

Aug 21, 2015
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Looks like I'm getting a new motor.

1993--->2003--->2013--->2023 +1 . . . . . . 31 yrs . . . . .
its about time.
You 'soitanly got yer munnys worth !
 

73's de Edd

Aug 21, 2015
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His / is the same old vintage home . . . . . . at the 529 addee.. . . Built in 1931, renovated in 1986
BUT, with tear downs and new architectural rebuilds to the neighbors to either side of it .

Also it shows up at at ~11:00 on this one . . . . .
 
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danadak

Feb 19, 2021
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I just cleaned the contacts on the C start centrifugal switch in my table saw
motor and the other push on contacts, and all is well again. I used 800 grit
sand paper, then flushed the contacts with alcohol.

Regards, Dana.
 

73's de Edd

Aug 21, 2015
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Indeed Dana . . .that is one valid and GOOD supplemental suggestion.
Particularly if this motor is used around woodworking and having micro fine sawdust floating around an depositing in every crevice.
Or having micro fine dust floating around from any other materiel.
In my case it was my motor of twice the speed of that one shown . . . . but still 125V 1 phase powered .
At rare times I'd go to the saw and turn it on and only hear a BUZZ for about his mentioned / described time, until the round KLIXXON thermal cut out breaker would snap and cut power off.
Being in a hurry to get that job done INSTANTLY, I would just lift the motor enough to then be able slide l the drive belt off the end of the pulley.
I wrapped inside of that motor pulley, enough venetian blind "rope", in the direction that will have the motor running in the proper direction. Then done a hard pull on that rope end to get that motor spinning and then flipping on power.
SUCCESS . . . . . IT RAN . . . . I then I dropped the belt into the pulley groove. Left the saw running until job was completed.
THEN at a more convenient time later, I cleaned up the sawdust coated / thereby insulated contacts.

Gauthack . . . . you need to do just that rope trick, as I described, to see if the motor runs, with you providing that initial spinning mechanical boost..
PARTICULARLY, if you put your nose down to the motor vents and don't smell the distinct and acrid odor of burnt magnet wire insulation.
Also, if you used that motor enough you should have noticed there always being an initial powerful noise as the centrifugal switch is starting up being closed and initially has the start up capacitor connected into the start up winding. There is a very distinct snapping noise as that mechanism scissors out and reaches its mechanical travel limit, at the same time the switch portion has opened up and disconnected the start up capacitor, since the motor is now powered solely by the motors running winding.
Centrifugal action of weights keep that switch open circuit, until such time that you cut motor power . Then the slowing down of the motor will
have some spring loaded counterweights hit a speed threshold where you will hear a distinct SNAP again. They now have the switch engaged for the next time you want to power up and start the motor
BUT that absolutely cannot t happen, if you have 2 coated contacts that are not making connection to each other.
I hope that this actually proves to be your problem.

73's de Edd . . . . .
 

Bluejets

Oct 5, 2014
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I just cleaned the contacts on the C start centrifugal switch in my table saw
motor and the other push on contacts, and all is well again. I used 800 grit
sand paper, then flushed the contacts with alcohol.
Can be ....if indeed it has a cent sw.
Many do not.
 
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