Repulse start induction run question

[KMinAF]

I have an old Craftsman table saw that has a repulsion start induction run motor. About 18 months ago the motor would not self start meaning I would have to spin the shaft to get it going. I dis-assembled and cleaned everything even going so far as to disassemble the shorting ring (necklace) to clean the corrosion of of the little "bricks". Using my lathe I resurfaced the commutator and recut between the contacts. After reassembly and installing "new" used brushes it still will not start unless helped. It makes a loud growling noise and "locks" into one position as though being pulled in two directions at once. If I adjust the brush plate to the clockwise setting I can sometimes get it to respond but not so when rotating it to the counter clockwise position. It is configured for 110 volts. Any ideas or suggestions?

 

[OldDoItAll]

The shorting necklace can be tricky. If the spring is not pretty much perfect it wont work right. owwm.org will have some good info.
I read a good article on how to repair one a while back but can't find it now. I think it was http://wiki.vintagemachinery.org/Unisaw-Bullet-Motor-Repair.ashx but the link doesn't work now. The article showed how to make a spring and what to make it from. It also showed how to test it's operation by chucking the armature in a lathe.

 

[Jack_K]

My guess would be that there's an open circuit in one of the armature windings.

 

[walta]

My wild guess the shorting neckless is not retracting and it shorting out the repulsion.

Could you spin the armature on a lathe and watch the neckless in action?

Testing the armature for shorts with a growler would be the next step in a motor shop and some shops might a agree to test it.

Walta

 

[OldDoItAll]

The link I posted is working today. It's for a Unisaw bullet motor but the necklace should be about the same.

 

[KMinAF]

Thanks for the suggestions and info!

 

[OldDoItAll]

Necklace shorting spring for Unisaw on Ebay if you need one, may or may not fit your Craftsman.

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