Rewound a motor

[Sparky2]

I rewound a motor as an experimental thing. I thought it might be fun to get into. It was a REEDY 27 turn motor from 15 years ago. Everything was pretty new because it was pulled after just a few batterys and swapped for something better. Has not been used since.

I decided to make it a 40 turn motor. Bench testing showed promising results. Upon installation I have noticed quite a bit of heat (way too much). When you stall the motor or stop and try to restart, it will just arc across the brushes. Push starting will get it going again.

Had this been successful, the installation should be a non issue because a 35 turn motor was just fine there (same gearing and all).

If it matters, this is an SCX-10 with the large (20 I think) pinion - and factory spur.

I wound the wires just the same as factory, but with more turns. The wire used was some radio shack magnet wire (green, but I'll try to find the size).

What likely went wrong?

If I can find the mistake, I'd like to try it again with larger wire (there was a little room left) - and maybe go for 30 or 35 turns this time.

[Sparky2]

Took it apart and resoldered a few things just incase something came loose or didn't connect well. It doesn't seem to have a dead spot any more. I still kindof wonder about the heat though. I cleaned the brushes and bearings really well, then lubed it. Now it draws less juice.

Kindof fun I must say.

[jamesdicken]

Do you have the timing cranked way advanced?

[Duuuuuuuude]

The first motor I ever wound did the same exact thing, but I don't remember what it was that fixed it. I've never had any more of them do it either.

btw: you might want to look into a comm lathe if you're going to do more. Makes them run much better being true and clean...

[Sparky2]

To be completely honest, I didn't know motors could be timed. I did a search on such a thing, and the general idea is that certain stock motors cannot be timed. I believe this is what I have. There is no way to change the relation between the comm. and the armature, nor is there a timing ring in the end.

As for the lathe, I may look into buying one if needed, but do you think using my regular metal lathe with a collet on one end, and holding the other with a live center would work?

[Duuuuuuuude]

Originally Posted by Sparky2

To be compleetly honest, I didn't know motors could be timed. I did a search on such a thing, and the general idea is that certain stock motors cannot be timed. I believe this is what I have. There is no way to change the relation between the comm. and the armature, nor is there a timing ring in the end.

How did you get it apart? Two screws? Bend back a crimp in the can? Is there a tab molded into the endbell and a slot in the can?

[Sparky2]

This one has 2 tabs that bend into slots in the end bell. The end bell has 2 screws that hold the brush holders and spring posts in place.

I bent the tabs back, pulled the brushes, and rewound the motor. Since this was experimental, I did nothing more. It got reassembled just as the factory had it.

Once I went back in, all I did was resolder the winding wires into their hooks, clean the crap out of it, and lube it up.

It seems pretty good now, but either I did something wrong - or a 40 turn motor is alot slower than I thought.

[Duuuuuuuude]

Originally Posted by Sparky2

This one has 2 tabs that bend into slots in the end bell. The end bell has 2 screws that hold the brush holders and spring posts in place.

I bent the tabs back, pulled the brushes, and rewound the motor. Since this was experimental, I did nothing more. It got reassembled just as the factory had it.

Once I went back in, all I did was resolder the winding wires into their hooks, clean the crap out of it, and lube it up.

It seems pretty good now, but either I did something wrong - or a 40 turn motor is alot slower than I thought.

Yeah, can't set timing on those. Others you can loosen the screws and rotate the endbell to change the timing.

40t's are fairly slow, but have you tried it in reverse? Is it faster that way? If the timing is advanced, it'll be noticably faster in one direction than the other.

[Reflection]

I used to wind my own back in the day. Loose winds will cause heat. Keeping all the winds snug and all equal will give the best results. Takes a little more time and dedication doing this,but they do work better when wound correctly. Another thing that will create heat is not having enough wire on the arms. Say you wound a 35t using the red wire. Besides being weaker than cat pee,it'd run warmer.

Anything more than a 35t,you'll need to use the green wire from Radio Shack. 35 turns of the copper color fills the arm up pretty full.

Winding a faster motor (lower turns) more care needs to be taken to "balance" the stator as in winds being tight and equal.

I'd imagine a regular collet lathe would work in cutting the comm. Don't bog it down with a big cut though.

[Manning]

I'm guessing it has 24 degrees timing, and maybe an armature with a slot (or slots) in it since it's an old "stock" motor.

That much timing and a slotted arm will always run hot no matter what you do. Both of these will make a tiny bit more power at the expense of a bunch more amp draw. Amp draw makes heat.

Might be too small of wire too.

Since it's a Reedy, it should have a round can. Find the timing tab on the endbell, cut it out then put it back together with zero timing. The magnets are oriented perpendicular to the imaginary line from between the motor screws. Right now the brushes are at a big angle to the imaginary line, turn the endbell so the brushes perpendicular to that imaginary line. That'll cut the heat a ton, and reduce the rpm, and make more torque. You could just put the motor together, hook it up, then turn the endbell it to where it rpm's the lowest. Will end up at the same place. Then use superglue to hold it together.

Lots of variables with winding motors. Fun to play with, but it's tough to beat a motor built by somebody with a bunch of experience doing it.

[Duuuuuuuude]

Originally Posted by Manning

Then use superglue to hold it together.

Really? Not that I'm calling you a liar, but I wouldn't have thought that it would hold together...your talking about gluing the endbell onto the can, right?

[jamesdicken]

Originally Posted by Duuuuuuuude

Really? Not that I'm calling you a liar, but I wouldn't have thought that it would hold together...your talking about gluing the endbell onto the can, right?

i think he was talking about a newer stock motor that has screws holding the endbell on not like yours with the bent tabs

[ROCKETRON1969]

the old 27 turn motors dont have com locks on the arm.so all you have to do is heat the com up a little and twist it counter clock wise a little bit before the epoxy dries you will turn the timing down.let cool after doing this and then true the arm in a com lathe.that should fix your over heating prob.

[team3six]

Well maybe this will help from the man himself
winding a motor

and some more things
http://www.wonderhowto.com/how-to/vi...ontrol-225234/
http://www.rcgroups.com/forums/showthread.php?t=715677

[Manning]

Originally Posted by Duuuuuuuude

Really? Not that I'm calling you a liar, but I wouldn't have thought that it would hold together...your talking about gluing the endbell onto the can, right?

Yep, done it many times.

[Robbob]

Super glue will come undone from the heat, and stink like a b1tch but it does hold together. Use to do it to hand out race motors years ago.

Your can probably doesnt have the lock ring in it to adjust the timing seeing that it has the factory old shool tabs on it. Try to find someone with a modified can and endbell, even a plain Integy black can would work as long as the magnets havent been heated to much.

When you soldered the wires to the comm tabs you may have also heated and warped the comm. A lathe is a good thing to have for anyone with brushed motors. After you wind and solder them you should turn them down again on the lathe. My guess is if you spun it and marked your comm with a sharpie your gonna notice high and low spots.



RocketTron1969 - It depends how old it is, if its stamped Roar on the can it came in then it has to have the lock tabs. Memory says something like 1995 or around then Roar mandated this in production for stock 27T motors. The other problem is even if he could do it he would have to do it prior to winding.

[Sparky2]

It must be the timing or "copper saturation" that is the issue. The motor works fine for the most part, but there is still a bit of heat and it is just slow and gutless. I was ready for something slower in favor of some more torque - but that is not the case. I may just abandon this one and find something a little more mod. friendly.

If this were a science project in highschool, I'd have the grade for an operational motor - but seeing as I was shooting for more torque and longer battery life, it was a total failure.

Baby steps I guess. I'll probably get this down pat right around the time I'm ready to pony up for lipos and brushless.

[rex cars]

I think that if this was your first attempt at winding a com and it ran after you put it back together then you should consider that a success by itself. You ought to try at least one more before you give up.

[Duuuuuuuude]

Originally Posted by rex cars

I think that if this was your first attempt at winding a com and it ran after you put it back together then you should consider that a success by itself. You ought to try at least one more before you give up.

Agreed. My first one was crap. The second was a little better. The first 35 I wound got smoked, big time. So, I ended up getting several different sizes of wire online and tried it again. Made a 45, worked great, but not enough speed for me, so I whipped up a 35. Now, if I'm not running my Puller, I'm running my 35. Having the proper wire size is paramount. Being able to turn the comms was a BIG plus also. Makes quite a difference.

I tried brushless and wasn't terribly impressed. Tons of torque, but they chatter at very light throttle inputs, and will sometimes stall. Brushed owns brushless when it comes to crawling IMO.

[2500hdon37s]

Originally Posted by Duuuuuuuude

Agreed. My first one was crap. The second was a little better. The first 35 I wound got smoked, big time. So, I ended up getting several different sizes of wire online and tried it again. Made a 45, worked great, but not enough speed for me, so I whipped up a 35. Now, if I'm not running my Puller, I'm running my 35. Having the proper wire size is paramount. Being able to turn the comms was a BIG plus also. Makes quite a difference.

I tried brushless and wasn't terribly impressed. Tons of torque, but they chatter at very light throttle inputs, and will sometimes stall. Brushed owns brushless when it comes to crawling IMO.

ROCK ON BROTHER!!!!