Question About Electric PTO Clutch Field Coils

[Bret McFarland]

I finally found a good 982 PTO Clutch (hopefully), the seller claims it works. These are getting rare and new ones or NOS are crazy expensive. This one that I am buying has a field coil that seems well preserved in a layer of grease. The one that I have that is bad -- has a field coil that shows the resin covering over the coil has cracked. So I am assuming the cracks have allowed moisture to enter and corrode the windings and ruin it?

The one that I am buying doesn't show cracks but it shows the resin covering as bubbling-up underneath in places. Is there anything I could do to help preserve it from going bad, or should I just leave it alone? Thanks

 

[rbedell]

I have used high temp silicon as a sealer, and if chunks are missing, I use JB Weld. Both have worked for me.

 

[Bret McFarland]

Thank you Roland!

 

[jstewart]

If the outer insulation is going south, it is a matter of time before it shorts out and lets all the smoke out.

IIRC, J B Weld doesn't have very good dialectric ability, but for low voltage it may be ok.

Any electric motor place could rewind a coil, had one done a few years ago for a 70 year old machine tool.

 

[Bret McFarland]

If the outer insulation is going south, it is a matter of time before it shorts out and lets all the smoke out.

IIRC, J B Weld doesn't have very good dialectric ability, but for low voltage it may be ok.

Any electric motor place could rewind a coil, had one done a few years ago for a 70 year old machine tool.

What I have found is that most electric motor shops won't touch it, and it's because of the very fine wire. I recently talked to a guy at a good local shop who said that the originals were machine wound and it's very hard to by hand. And he said that the coils stop working because corrosion eventually eats through the very fine wire, and trapped moisture feeds the corrosion. This shop restores older motors and has an oven where they actually heat the windings after they clean them. Then they spray a coating of epoxy on the windings. I have found only one person on craigslist who does rewind these coils -- now they're price is about $300 w/shipping. I think would rather take my chances on a used one that works, and maybe clean it up and dry it out, and then re-seal it.