Victory! Replacing Motor Leads

My Andrychow scrapyard rescue lathe motor leads were made of inferior insulation which crumbled away.

Thought I would replace the leads. Found Forrest Addy's instructions and dove in.

"Before you start: lead identification has to be preserved - fix that into your head. Mis-ID a lead and you've set yourself up for all sorts of problems and maybe a fried motor.

The leads run back to their respective windings and since the motor has been laced and varnished they may be difficult to dig out. The leads pass from the windings inside the frame to the J box. They may be fused into a single mass because of the varnish. This has to be patiently dismantled and the individual leads reased out. Once the leads are all out and exposed you can replace them using either marked lead wire you buy from the motor shop or you can make up metal or plastic tags or floaters. Consult with the motor shop. Replacing the leads one by one is a matter is excavating out each lead to its junction with the winding and replace it using a solder joint insulating it with either varnished cambric or glass sleeving or fabric electrial tape. Allow plenty of extral lead for later trim and final ID. Doctor up any ragged varnish encrustations, thread the leads out the J box, bundle the leads neatly and re-lace the leads to the motor windings. "
Repair ideas for 25 hp electric motor lead?

The original lacing was a small diameter string. The 'local' motor shop 120 miles away had only flat tape style string and was substantially larger in x section.
The original leads were some metric size, solid wire about 13 gauge. I got 12 gauge stranded from the motor shop.

6ft of wire and 25 ft of string, $17.

When I cut out the old lacing I saw that they do a looping arrangement which creates a knot below each pass around the windings and leads. The knot is down below, can't be seen or untied. So I had to cut at every loop.




The factory just put a dab of solder at the end of the winding/lead connection which I thought was odd.


I found out why when I tried to twist and solder. That thin coating, insulating varnish they have on the windings is very hard to remove, so they just soldered the cut at the exposed ends.

I tried various solvents etc to remove the coating before soldering, none worked, didn't want to try paint stripper, tried burning it off, no go,, so carefully scraped off the coating.
Hard to see where it was completely bare and where it wasn't.
But I found out when I went to solder. The solder absolutely would not flow if it has any residual coating.

Finally got a good connection.


to be continued.....

Didn't have any known ozone resistant shrink tubing so I coated the connections with insulating varnish after cleaning off the flux.
The original connx were corroded.
MG Chemicals 4228-225ML Red GLPT Insulating Varnish 225ML Bottle from Ebay, $22.

Then slid the factory sleeves back over the connections.

Because the leads were larger diameter with far more insulation, plus the lacing string was larger too it was hard to cram it all back in there.
I used plastic cable ties to pull it all in place before lacing, carefully pushing the connections down where they originally were.

Things were going great, I figured out the 1st loop must go down through the inside space of the winding, out and over the top and then a second loop inserted through.
Doing it the other way, the knot and lacing bind and you can't cinch it up.

You don't just wrap the lacing around the windings, just keep working the loops.

Then ugh, it struck.... I ran out of lacing.
*%!!%$. Since the old lacing came out in bits and pieces I had no idea how many feet I needed. Bought 25 ft and thought that would have been plenty.
Not! Made it only about 60%.

Another couple of weeks to wait till I could justify driving 120 miles one way for $2 worth of string.
The motor shop really doesn't sell this stuff, just did me a favor by doing so.
So I couldn't really ask them to ship it.

Back at the motor shop, holidays and a different guy went in back to get more string. I gave him a sample, but noticed it was slightly larger than the sample I gave him. No big deal, I thought.

Ugh, the flat tape string was harder to lace, cinch and tie I am sure than the round. And the larger lacing was harder yet. It just wanted to bind and made cinching tough. The knot just didn't want to get down low like the string and the smaller tape did.


But it all had plenty of clearance between the housing and armature.
Proceeded to slobber on the insulating varnish.
Way thicker with more solids than the original varnish.
And unlike the lacing I have enough varnish to do a hundred releading jobs. lol
Should have bought a much smaller container.


Parked it by the wood stove to cure, that made the whole thing a solid mass.
New bearings and it runs great.

Only took about 8 hours, over 4 weeks and 480 miles of driving! lol