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Discussion Starter #1
Does anyone happened to have saved this thread about rewinding a clutch coil? I can get the pics but would really like to read the thread! Looks like I'm gonna have to either buy a new coil (ouch!) or rewind mine. Would really like to try the rewind.
Thanks!!

(Message edited by robb318 on December 12, 2006)
 

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I'm with you on that one Jim, that was a great step by step thread. It gets my vote as a keeper in the Technical archive section...
 

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Jim and Crystal

Maybe you could e-mail a moderator to help you.

I recently bought a new field coil at JD for a 318 for $120.00. Is it really worth all the trouble and expense for the correct gauge wire, correct # of turns, correct epoxy, etc. etc. only to find out that it doesn’t work right anyway, not to mention all the time you wasted. Sometimes you can be a penny wise and a dollar foolish. I don’t know the exact reason why you want to go that route, it’s none of my business, but I just can’t see how it can be cost effective. Just trying to help!

Jim
 

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Discussion Starter #4
Thanks for the replies! Still think I'm gonna try it if I can get the info, certain satisfaction in doing something like that myself!!
 

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Jim Aldinger - I totally understand your point of view and it makes 100% sense. However, I just think that half the fun of restoring these old tractors is the satisfaction of fixing it yourself. I shudder to think of the time and $$$ I've spent getting my RF 110, 212 and 216 back in fighting shape.

Would I do it all again? Absolutely! Re-winding one of these coils falls in the same category.

As a hobby, I used to hand wind my own guitar pickups. Built myself a winding machine, cut and ground the magnets and bobbin material and wrapped them with about 10,000 turns of 43 ga. wire. That's about as fine as a human hair. Could have gotten a store bought one for about $50. Was I being sensible? Naaaa... But there was something about those pickups that sounded just a little bit sweeter to my ear because I had built them myself. Not to mention the fun I had going through the process.

I wouldn't mind trying to rebuild one of these electric PTOs. Might be fun and It'd probably give me something to do to keep me out of trouble!

Just my $.02
 

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No problem!! I definitely agree with both of you. The main thing in a persons life is to be happy! I've done stuff like this before and yes there is a lot of satisfaction in knowing you accomplished it yourself and it works the way it's supposed to.
When I first read J & C's original post I thought it was strictly a money issue. Sorry I didn't know. I hope it works out for you and if I find anything out I'll let you know!

What model and year tractor is it for? I assume it's the front PTO.

Jim

(Message edited by jdfan on October 06, 2006)
 

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Jim & Crystal,

So far I found this:

Re: JD 318 - please help me and my dad in reply to Kent of SW MO, 05-11-2005 05:14:44

If it's just the coil, you can rewind a new coil and repot it with epoxy glue. On mine, the old epoxy/sand mix broke down, and the winding was destroyed. I removed coil, determined number of turns, and wire gauge, and rewound it with similar gauge copper in place of the aluminum, and increased windings by about 10%. Cleaned out old epoxy out of ring, sand blasted interior, and repotted new coil with a couple tubes of 30 min. epoxy. Has held up for a number of years.
 

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Discussion Starter #8
Once again, thanks guys! JD people are in a class by themselves!! Gonna be a few days before I attempts this, will definately post results!!
 

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Discussion Starter #9
OK guys, cleaned the old wire out of the pot, determined wire size, bought probably three times as much wire as I will need off ebay for 25 bucks. Will post pics and results as soon as wire gets here. Think regular old 5 minute epoxy is OK or should I use something like jb weld?. Also, I should have wire left over if anybody wants to try this.
 

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Jim - I used to use wax as a potting agent on my guitar pickups. Heat up the wax until it's liquid, put the pickup in the wax and wait until the air bubbles stop, remove the pickup, suspend it and let it cool. The wax hardens and solidifies the wires in the coil.

I don’t think that wax would work in this application, but you still want to solidify the coil when you are done with the winding. An alternate method I used was to buy a quart of sanding sealer (a thicker type of lacquer) and dip the coil in it, repeating the same process as above. This would give the same results and should work in a heated environment. Five minute epoxy or JB Weld would not work for this as it is too thick to fully penetrate the coil. - j
 

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Discussion Starter #11
Good point John! Could use the sanding sealer first and epoxy for the final fill. Or maybe, I have some clear acrylic and activator left over from some body work. That stuff sets up hard as a rock, and is as thin as water. What do you think?
 

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Jim - The clear acrylic and activator sounds like it might be the best idea of all. I think I'd go that way especially since you do have extra wire(!).

The potting was done for the guitar pickups to stop any vibration of the wire which would induce feedback into the amp. I can imagine that there’d be way more vibration in a coil sitting on the end of a crank of a single cylinder Kohler! The potting in that application would keep the wire from vibrating and wearing the insulation off the wire causing a short and coil failure.

On many of the coils that I've seen, they’ll wrap a cloth tape completely around the coil after it’s been potted to protect the outer windings and keep out foreign matter that could abrade the insulation. You could do that as well (don’t know what type of tape they use but it almost looks like a cloth medical tape only thinner) or… make a mold of some sort that could be easily removed and pour liquid epoxy over the entire coil to seal it. That might be a pain to do but it would work as well…

Good luck! I look forward toy seeing your progress and your pictures! - John
 

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Discussion Starter #13
I think what I will do is lay a layer of acrylic with very short fiberglass strands in the frame itself, 1/8th inch or so. Let it start to set up, lay the new coil in, and pour the acrylic over the whole thing. Should work its way into the coil and insulate and immobilize it. May mix some fiberglass into the final 1/16 or so for strength. Sounds good in theory, and just might work!
 

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Jim and Crystal.

I assume the wire you bought is enamel coated, I HOPE!! Maybe you should test whatever sealing agent you use on a piece of the wire to make sure it doesn't react with the enamel.

What gauge wire did you get? I have a big roll of enamel coated #26. Maybe if my coil ever goes bad again I'll try rewinding it.
Jim
 

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Discussion Starter #15
Jim
I bought sure 'nuff magnet wire, 22 gauge. Miked my old wire and 22 gauge was the closest. Glad you said something about the enamel, I hadn't thought of that. The acrylic is pretty hot, afraid it would eat through the enamel. Will have to do some experimenting before deciding what to pot it with. May do what John said, dip the coil a few times in sanding sealer to seal the coil, then pot it with epoxy.
 

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If you go back to my post on 10/6, They mentioned using a 30 minute epoxy which I would think would give the stuff more time to settle in around all the wire. If some method were used to vibrate the whole thing at 60 Hz or so, then I would think the stuff would really work it's way in to the coil. Something like vibrating concrete so it eliminates all voids.

Now for another idea. You said you saw pictures of this being done. I assume you saw the same one I did where he wound the wire on a spool the correct dimension which can be disassembled when finished. That’s a real cute idea!! Now, when I was in grade school, ( 50 years ago ), my science project was to build a little electric motor. My dad wound that same # 26 wire I mentioned earlier on a small spool. On every layer of wire he painted on a coat of clear lacquer and then before it dried he wound on another layer and did it again & again until it was finished. Now when the lacquer dried he took the spool apart and he had a nice solid coil of wire. To take it one step further, you could take this coil and put it in the pot and now dump in your epoxy! I’ll just bet you that puppy ain’t goin’ nowhere for many years to come!!


Jim
 

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I've accidently come across some pictures that haven't scrolled off into never never land on this subject in the gallery.

http://tinyurl.com/y66ear

Hope this helps a bit. Wish someone had saved that original thread on this subject. It was a good one.
 

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Jim and Crystal,

Those are the pictures of the coil I made for my 430. I'll give you some thoughts:

I work for a company that makes motors so I was able to use all of the good stuff. The wire I used was "bondable" wire. After the coil was formed, it was heated to about 100°C by running 110V AC through it. This heat activated an adhesive insulation on the surface of the wire and bonded it into one solid mass. The coil was then wrapped with woven nylon tape and further encapsulated with a thin polyester resin. The coil was potted into the housing using an epoxy resin.

If I were to do it at home here is what I would try.

Build a form similar to the one I made. It has to be able to come apart so you can get the coil out. Make it so it can be lined with waxed paper. You have to drill a small hole in the side next to the inner hub for the free end of the wire to come out.

I would use 2 hour epoxy. Thread about 2 feet of the free end of the wire through the hole and coil it up and tape it to the outside of the form. I used a big slow drill to turn the form. Wind a layer of wire on the form. Be very careful that the wire makes a smooth, neat layer. Take your time; this is where patience pays off. As you finish the first layer, brush a thin layer of epoxy on the outside of the first layer. Now wind the second layer. Again, take your time. When this is done, brush on another layer of epoxy. Continue this process until the coil is wound. Make sure your last layer ends on the same side as the free end that you ran through the hole in the side of the of the form.

Now, let the coil cure over night. Disassemble the form to remove the coil. Be careful of the free end that you ran out of the hole in the side of the form. You should now have a bonded coil with two leads on the same side, one on the inside and one on the outside of the coil.

You have to attach lead wires to the magnet wire. Carefully sand the insulation off the magnet wire about 2" from the coil. Now cut the magnet wire at the end of the sanded area and solder on the lead wires. Make the lead wires about 2 feet long. Put heat shrink tubing about 2" long on the joint and shrink. Run the wires next to each other and have them exit the coil on the outside diameter. Make sure the splices are within the area of the coil and are included in the wrap in the next step.
 

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Potting Coil Cont.

The coil should be wrapped in something before it is potted into the housing. I would recommend flat cotton athletic shoelace. Wrap the coil, overlapping the shoelace on the inside diameter and having spaces between on the outside diameter. The purpose is to keep the coil from touching the housing during the potting operation. Also, check the coil resistance with an ohmmeter at each step to make sure that it didn’t short or open.

Test fit the coil in the housing. The leads need to run out of a hole in the back of the housing. If it fits well, remove the coil and place next to the housing with the leads remaining in the hole. Mix up some 30min epoxy and put a small amount in the bottom of the housing. Turn the coil over and paint the back side with some epoxy. Use a heat gun to warm the epoxy on the coil which will lower its viscosity and make it flow into the cotton. Don't heat it too much or it may smoke and burn (it is advisable to experiment with this technique prior to pouring the coil.) With the cotton wrapping fully saturated, turn the coil back over and place into the housing. Pull the lead wires through as the coil is being placed. When the coil is in place, plug up the space around the lead wires with clay or putty to keep the epoxy from dripping out.

Now pour a small amount of epoxy on to the top of the coil and heat it with the heat gun. This will cause it to flow over the sides of the coil and saturate the cotton wrapping. Keep adding the epoxy in this fashion until the housing is full. Now let it cure overnight.

You should now have a completed coil. Add a spade terminal on one of the leads and ground the other lead and it should work fine.


Bob
 

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Jim & Crystal,
The link that Jim Q. mentioned was the one I eluded to earlier. I assumed you saw the same one, but if not Jim simplified it. Bob Gehret, who created this link, e-mailed me and gave me his phone # about this subject, but I don't want to give it out unless it's ok with him!

In your other thread, you said you were still waiting for the wire. What happened with the wire you got off Ebay?

Jim
 
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