Mark v won't start just humms

[59giants]

Hi I'm a newbie. My name is David from NorCal I've had my shop smith about 15 years helped build my house and many other things with it sadly it doesn't start right now ,with the aid of this forum I've taken it apart and cleaned it up.it has a GE 1 1/8 motor 1981 model I removed the belt from the motor and it still won't turn on its On my way! the top end turns freely so I'm not sure what too do next if anyone can point me in the right direction I would be grateful.

[billmayo]

A common problem. A motor will hum if no power is being aplied to the start windings on startup. I find the centrifugal start points are not making good contact due to dirt qnd grit (crud) gets on the points and causes the points to burn resulting in lost contact. Many times putting the headstock in the drill press position and tapping the motor pan with a large rubber hammer will loosen the crud to where the contacts will make contact. Otherwise you will need to determine how to get to the points to clean them. Some motors with a flat end casing will require the end casing to be removed. On some AO Smith motors, the points are located in a small compartment on the end of the motor. Motors that use a start relay box are different and can be hard to trouble shoot. Contact me for more information.

Warning: do no apply power for more than 1 sec if the motor hums. Repeating applying power can burn and destroy the run windings which kills any future use of the motor.

[cooch366]

This has happend to me twice on a 80's 500. The first time I took it to an electical motor repair person.

He told me that with the unsealed type of motor that is used, sawdust is getting into the contacts causing the problem. I was also told that he cleaned (blowing it out with a compressor & air) will / did fix it.

So the second time, saved myself a trip to the repair shop. Got out the compressor and blew the snot out of it. I removed the motor from the housing to clean it and it did the trick for me.

As Bill stated, hopefully it is not caked on and the compressed air will work for you.

FWIW, YMMV

Good luck.... Steve

[dusty]

If you blow out the headstock and motor a bit more frequently, maybe this won't happen at all.

[59giants]

Thank you for help. I've already blown It out and cleaned it pretty thoroughly taking off the back cap of the motor with the 4 long bolts and using compressed air as I said after that I tried the motor without the v belt and it would just rock and hum but not turn. Not sure what I should do next.

[enyoc]

if you spin the motor will it keep spinning? (careful!) if so it's the capacitor. check the connections and replace as necessary.

here's a video that might help...
http://www.youtube.com/watch?v=4k4c998kLKc

[59giants]

No it doesn't continue to spin if you turn it .

[ipbarnard]

Mine has done that twice over the years.

Once it was the switch. It was not letting enough power through the switch.

The second time it was the points on the back of the motor. Mine are easily accessible and all I did was clean them off and it ran fine.

You may have to take it to an electrical motor shop.

Thanks,

[JPG]

Thank you for help. I've already blown It out and cleaned it pretty thoroughly taking off the back cap of the motor with the 4 long bolts and using compressed air as I said after that I tried the motor without the v belt and it would just rock and hum but not turn. Not sure what I should do next.

Do you have a multimeter? Ohmmeter more specifically.

[59giants]

Yes I have a multi meter. I just got off work thanks for your help.what would I be checking with it I'm not exactly an electrician as you have no doubt deduced.