500KW generator - Barrel coils removal

Hey All.

Am currently working on disassembling a 500KW generator, and am starting the copper removal process. The armature went well, and I recovered 200 lbs from it alone. Next big piece to tackle is the barrel, and I'm wondering if anyone has any experience removing the copper - or how NOT to remove the copper.

I have the disassembly video on youtube under White Squirrel Enterprises so we can see what I'm dealing with. It looks like it'll be a doozie, so any suggestions or past experiences with something like this would be welcome!

Thanks for posting the video and welcome to the forum.

That one is well out of my range so i may not know what i'm talking about. To me ... the barrel looks like any other stator ... just bigger. Same procedure as doing a smaller one. Cut the outer jacket away along the seam and the stator inside falls out ?

https://www.youtube.com/watch?v=ZUwKbik0Ljc

It looks like the windings are all epoxied in, but that's where I was thinking of starting - I just hate the mess from cutting copper with a grinder, but can't fit the sawsall in there.

I just took appart the small stator, and it was a bigger PITA than I thought - I tried a few methods then ended up having to air hammer the epoxy out, which made a giant mess. Hoping to take a shot at the large one later this afternoon.

I was watching another youtube video where they were re-winding the stator on a large motor. They used an oxy/acetylene cherry blossom heating tip to burn the windings before stripping it. I suppose you could use a flame thrower powered by a propane BBQ tank to do the same job. You would want to do it outside though. All around ... not much fun any way you do it. It would be one thing if the windings were varnished but epoxy would be extra hard to deal with.

I hope it goes as well as it can for you.

So they are NOT epoxied - there's just a plastic slug that acts as a lock. But that's where the good news ends.

I tried cutting the ends off like a regular stator, but I'd need a 6" disc to get to the rearmost windings. Has some luck peeling the top winding out by choosing the first few wires to tug on, but that would have taken forever...then it would have block off the rear winding. The sawsall is NOT cutting through the end of the winding, even with a Torch blade.

So hardware stores are still close today, and I can't refill my Oxy-Acet tanks today - I think gouging out the laminated core would probably have been the fastest course.

I'll get back at her this morning, hoping to think of a new angle to try after a nice pot of coffee.

You should consider a diamond blade for the cut off / grinder.

I believe you mentioned a gantry crane in your video. Once one end of the windings are cut, can you hang it from the other end and only grab a couple of windings at at time. Pick it up off the floor a few inches and see if gravity will do its work. May take a little bit of time.

Diamond blade for the grinder would be a good idea.

I tried letting one of the winding hang, the stator is around 1500 lbs, but nothing. Tried going down to a few strands, and they just broke. What doozie! I even tried a bottle jack inside of the housing on one of the winding - it pulled them a little bit, but ended up snapping the wires.

I've got about a third of it done right now, seems I found a comfortable setup where I can peel the wires away with a small and large pry bar. I'm hoping once the outer ring is done, it'll have loosened everything enough that I can try hanging and use gravity's help while prying or hammering.

I found that a sharp carpenters chisel cuts thru Copper wires like a hot knife thru frozen butter.

I'd try using a compressed air powered chisel with the chisel sharpened up. They are cheap and a very handy tool to have.

Haha that's funny, I said exactly that in my copper extraction video. I use an air hammer/chisel on almost all my copper: I hate the grinding dust from copper, and I do find it cuts through wiring quite well. What I need to do for this piece, I think, is modify a blunt bit so it pulls more than cuts, specially when pushing the slugs through the stator housing.

With one end of the Copper coils cut off. Stand it up on end outside in a good spot & put some scrap wood in it & set it on fire. That will burn enough of the 8nsulation out to be able to pull the Copper wire out the top by the end loop.

But see if you can just pull that loop out first, a chain lock, overhead crane/ winch would do it.

I would love to fire it up and burn all that out, but we currently have a fire ban :/ I still like the idea of using gravity, so I think i'll fab up a locking plate with a couple of bolts to clamp onto one end of the loop and pull it up with the crane. I think a straight pull, like mentioned, would be the only option since the wires keep breaking as soon as there's a pull on any angle.

I definitely need to come at it from a different angle - all the other components are stripped and I put the new video up today, am hoping I can have that large stator stripped before the weekend.

Check out the video below and see if you could adapt some of the concepts to your own situation .... especially the idea of pulling evenly on the coils so that they come out all as one. One would think that splitting the stator crosswise would make the pull a lot easier too.

You wouldn't happen to have a backhoe around anywhere would you ?

Ummmm ... fun with heavy equipment at it's best ! :)

https://www.youtube.com/watch?v=l3SvzMToasA

Oh. My. Wow. lol I felt something tingle in the bottom of my heart, there.

I have a 100 ton press at work, but this housing is way to big to fit anywhere... Will have to McGuyver something for the smaller stators after seeing that though :P

We also have a Pirhana metalworker that I think would do great to split some stators and cut the windings down.

I like it!

Hokay, so it looks like I've found the most consistent way to do this so far.


This has taken alot of trial and error to figure out the most efficient way to do so, but I'm sure if I had another giant gen set to scrap I could do it in 4-6 hours. So here's what I'm working with - should be done stripping it by the weekend.


I cut one side of the outer ring with an air hammer. Then, I peeled a few strands from the inner layer and put tension on them with the crane. The large pry bar is used to pull the stands OUT and tear them through the casings (pulling straight up did not work). I'm almost done all the inner bundles, and once that's done I'll use the same process on the outer ones. Hopefully I'll be sitting on a new giant pile of copper by the weekend.


Thanks for the help so far, everyone! Will update when everything's on the ground.

Finally freed up some time to finish this one up. Pulled 190 lbs of copper out of the stator, using the above method to get the rest of it out. Put that last video up - this was a fun one!

Gee ... the air chisel idea is pretty good.

I had a really stubborn rotor this afternoon. I don't have air tools but i had Bosch SDS hammer drill with a chipping point. Set it just on hammer mode and it buzzed the windings right out.