(Re)winding and building motors, tips & tricks, checks & tests - Page 12 - RC Groups
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This thread is privately moderated by Ron van Sommeren, who may elect to delete unwanted replies.
Nov 13, 2005, 08:52 PM
Originally Posted by DangerBird
I have had a motor pull out of one of these twice! Second time resulted in the need for a rewind. I had it very tight. I would suggest roughing it up a bit or some locktite.

Thanks for the report. It may save a few airplanes.
The KMS motor mount appears to have two "fins" that the motor holding screw pulls together. But, the fins are not even close to parallel and that would make it almost impossible to keep the clamping tight. Any vibration at all and I think it is likely to come loose. It looks like a faulty design to me.

Can the "fins" be bent to resolve this problem with out weakening them? That would depend on the type and quality of the Aluminum.
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Nov 14, 2005, 07:20 PM
Night Flying
Ron H's Avatar
Trying to remove Ca? Forget those long soaks in acetone! Try some PB penetrating lube. AKA PB Blaster or PB Knockerloose.

While using Ca to attatch a bearing to a mount, I slipped and glued the bearing too. Since the bearing couldn't spin, I figured I would lube it and use it as a bushing until I got a replacement. A drop of this stuff and 30 seconds later I destroyed the motor when the bearing worked loose.

Since the can was shot, I dribbled some PB on one magnet to see what would happen. 30 minutes later, I tried prying the magnet out. Surprise! All of them came out with just a touch from a #11. The stuff had wicked around the whole can.

Acetone may still be handy for a solvent to get the PB off but rubbing alcohol will do. The PB must be totally removed or Ca is useless. Fortunately this is very easy, but remeber to wash your hands before handling any parts that will be Ca'd.

The PB doesn't smell lovely, but it sure beats anything I've used that can break down Ca. Luckily I haven't tried on skin yet, but I'm sure it will cause less (0) skin damage than acetone or debonder. It doesn't evaporate either, so no cover is needed to soak parts and fumes are not a problem.

These were not lighltly stuck magnets. They had been coated several times and spun in a dremel (thanks olmod) Even with the thick Ca that was several months old, it took just a few minutes to lift them out and no prying was needed.
Nov 14, 2005, 09:17 PM
Foam Flyer
Depdog's Avatar

Nov 14, 2005, 09:28 PM
Originally Posted by Depdog
Site says it is retailed by NAPA and Murry's auto stores, that should pretty well cover the USA.

Is this the product that desolves CA?
"PB Penetrating Catalyst-Quickly breaks loose the surface tension of frozen parts and protects against further rust and corrosion."
Last edited by bz1mcr; Nov 15, 2005 at 10:28 AM.
Nov 15, 2005, 12:38 AM
Night Flying
Ron H's Avatar
Originally Posted by bz1mcr

Is this the product that desolves CA?
That's the stuff. Guess I should have put a link, but that's a pain from here. New magnets in the can now, and a somewhat different wind on the new stator. New thread to follow.
Nov 15, 2005, 01:49 AM
Team30 Micro EDF
NitroCharged's Avatar
australian online seller:

Nov 18, 2005, 10:16 PM
Night Flying
Ron H's Avatar
Update on the PB. Tested on a second can with more attention to details. PB does not dissolve or even break down Ca in any way. What it seems to do is wick between the Ca and metal, reducing the bond. BTW, soaking doesn't help. Some ingredient evaporates. Still, the magnets came right out after a re-spray and some prying.
Jan 22, 2006, 07:33 PM
Good Better Best quest.
olmod's Avatar

tacho aid for no loads.

sometime back i found a use for some of those white plastic gears found in cdroms, some are a nice firm fit onto a 3mm motor shaft ,to wich i glue a 2''~2,5'' disc cut from a heavy clear plastic packaging film,with one of those exacto circle cutters,to wich i stick either black or white tape across the middle, they run smooth as and easy to push on and get off.
Feb 05, 2006, 05:02 PM
Registered User
manuel v's Avatar
Orientation off magnets. you can't go wrong.
North and south not is necesary to know.
Last edited by manuel v; Feb 06, 2006 at 12:56 AM.
Feb 05, 2006, 05:44 PM
Nice tip.
Your diagram is shows flat magnets, but I think it will also work for curved magnets if they are first arranged in one long stack as in your first figure. After that as long as the marks end up together at every other joint as you last figure shows, you can't go wrong.
Feb 17, 2006, 05:21 AM
Registered User
LRK is 3 guys initials who invented that type of motor. I think it was originally for electric vehicles (much larger of course) and they were trying to eliminate cogging.

Classic LRK only has 6 out of 12 teeth wound. Distributed LRK takes half the windings eg. from tooth one and puts them on tooth 2 CCW (if tooth one was CW).

If you look here:
at the 12 slot/10 pole and 14 pole combinations he lists distributed and classic LRK winding schemes.

Look here at "Electric Motors" parts 1-5, he discusses LRK in part 3 but it's all good info.

Good Luck!

BTW, your calculations on copper density have nothing to do with Kv. The density affects efficiency, but Kv is dependant mainly on the # of turns. See my post here:

Your motor, OTOH, with 30 turns may not be too useful (it might be OK on 4-5S) but it was good practice. Super low Kv motors, unless run at high voltage are only efficient at very low currents.
Last edited by BeavrdamElectric; Feb 17, 2006 at 08:22 AM.
Mar 07, 2006, 08:53 PM
Wind is the devil.
Argyle's Avatar
GBv1.1 Kit

I found one trick for press fitting the shaft and bell to pass on to other newbies:

I used a bearing tube, fitted with a bushing (figured the bushing would be less likely to allow any shaft angle), and brand new stator to fit the shaft into the bell bore. I taped the stator, around the hammerheads, to ensure a snug airgap. I removed the plastic ring from the GBv tiny shaft (pushed through bushing) and began slowly tapping the shaft into the bell through the bushing/stator. I sat the entire motor over a block of wood with a hole in the center so I could push the shaft through the bell.

I didnt glue the bearing tube into he stator, so that I could remove the tube without having to unseat the stator. This was done so I could slowly set the shaft at the proper level to ensure the plastic ring would fit correctly with the bearing tube.

Once I finished, I replaced the plastic ring, and inserted it into the wound stator.
Mar 15, 2006, 02:03 AM
Registered User
manuel v's Avatar
Multiple wire chart.
Mar 27, 2006, 06:50 AM
Good Better Best quest.
olmod's Avatar
When gluing mags end to end or even side by side for that special
modify a strong crocodile clip by adding a 3mm square of plastic glued to one half jaw,after gluing in the first row of mags use this to clamp down on the second row magnet after positioning as close as you can then while clamped you use a nonmagnetic tool to push the mag into its final position then add loctite to the outer edge after about 10 seconds remove then jump a space and do the next magnet.cheers,
Apr 26, 2006, 10:47 PM
Good Better Best quest.
olmod's Avatar

olmods stator winder mk2

I have revamped my origonal design to allow me to wind longer stators, the chuck off an old drill is a good mod' it allows up to 10mm bearing tubes,the rest of the parts were from an old vcr plus some allum stock,loc-tite 480 black max was used to glue some of the parts together, its first job was a 30mm long stator wound with .83mm wire wich was no problem

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