Outrunners you've unwound? Hxt, Turnigy, Scorpion, etc.

[swbluto]

Please let me know how your experiences with different hobby-city or other outrunner motors has been with unwinding.

I'll start with mine:

The HXT 100-80-B, version 1: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=5142&Product_Name=Turnigy_80-100-B_130Kv_Brushless_Outrunner_(eq:_70-55)

Snipping the wires, it was a pleasure to unwind. I had to pull and yank quite often but it surely came out. The windings weren't "stuck" to each other.

The HXT 63-74-B, version 1: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=3890&Product_Name=HXT_63-74_200kv_Brushless_Outrunner_(Eq:5240)

Snipping the wires, it seemed like unwinding this one was like pulling teeth (Even though teeth are easier to pull). In the end, it seemed essentially impossible unless one were willing to do it one strand at a time out of the literally 1000's of strands. I gave up. This was even after cooking the motor to 450 degrees fahrenheit. It appears the windings were impregnated with glue to prevent them from coming loose, as I could tell by the two distinct layers of windings, the inner copper-colored flexible layer and the outer, shell-like stuck-together "dull whitened" copper layer.

I'm trying to find out which motors are rebuild-able if I ever need to. I just hate thinking that I spent $100 on a motor whose valuable components I have to throw away due to the manufacturing design decisions that encourage that type of waste. I'm looking at scorpion motors, but I'm quite cautious given their higher price tag and the possibility of it being non-rebuild-able. It'd be neat if there's someone who's tried to unwind an 80-85 HXT motor, as that's the other motor I'm looking at that would work for me.

 

[Thud]

S,
I have unwound a turnegy SK-5064. it was all epoxyed up as you described. I actually boiled mine in a pressure cooker for an hour to remove the stator form the bearing tube.

Regarding re-buildability. I would think it is just a matter of econmics tempered with your goal. If your time is worth more than the parts you are repairing then maybe not, especialy for a 1-off. However, if you are set up to do the work & want to experiment with winds & termination senarios, it would be justifiable. Setting up to rewind a $1200 pletenberg seems reasonable. I cant buy a spool of copper for the price of a tunigy 50-64.

The unwinding was a trial with a small side cutter & needle nose pliers. They globed the potting varnish very heavy in these things.
Re winding is the trial if you are going to duplicate the DLRK all these motors are confgured in.
Good Luck, I am watching with interest on your experiance.

 

[drewjet]

I rewound my tunigy sk motor. I don't recall it being all that bad removing the old wires. Scorpians are available as a kit, and are very good motors.

 

[An average human]

i know this is a bit off topic but the motor i have used is a scorpion S-4025 its small - 2000w and i have had it fail. The stator(?) spun and ripped the wires shorting and killing one of the many esc's i have killed. the motor has been run very hot, i have since changed the gearing, this may be the reason the stator(?) came lose. i have not tried to unwind but i should be able to find some pictures of the inside if it helps.

human

 

[swbluto]

i know this is a bit off topic but the motor i have used is a scorpion S-4025 its small - 2000w and i have had it fail. The stator(?) spun and ripped the wires shorting and killing one of the many esc's i have killed. the motor has been run very hot, i have since changed the gearing, this may be the reason the stator(?) came lose. i have not tried to unwind but i should be able to find some pictures of the inside if it helps.

human

That seems a bit weird. The stator would only spin if it weren't secured to the front (And I assume you had the front attached to somewhere, like a motor mounting plate or something), suggesting that the epoxy may have failed. They supposedly use high temperature epoxy, but it'd probably soften at high enough temperatures. It's pretty critical to gear it correctly to minimize heat generation, and I use my simulator for those kind of gearing predictions. But, also, the 40x motors aren't ideal for >700 watt EV applications due to the high internal resistance and, from what I can see, pretty high kV.

If you can see the inside, could take a small "poker" thingie (Like, maybe a pin or x-acto knife) and see if you can move individual windings? If it's tight, it won't move too much, but you'll be able to "easily" get inbetween windings. If it's not "easy", then that suggests they dipped it in varnish or some other type of glue which would make unwinding it / rebuilding it a bear.

 

[swbluto]

Regarding re-buildability. I would think it is just a matter of econmics tempered with your goal. If your time is worth more than the parts you are repairing then maybe not, especialy for a 1-off.

Yeah, you could say that. So far, I don't even know if it's possible to remove all the windings, so my current time estimate is something like 100+ hours to unwind it. I would like to try a kiln to see if that might work. It may not though. I'm thinking I may want to take advantage of another solvent: turpentine. It appears that wikipedia thinks it's a solvent for varnish.

I rewound my tunigy sk motor. I don't recall it being all that bad removing the old wires. Scorpians are available as a kit, and are very good motors.

Which turnigy SK motor did you have? I'm trying to find a pattern to which motors are likely varnished and not varnished.

 

[olaf-lampe]

I have rewound roughly 100+ industrial outrunners from copymachines, laserprinters and even motorcycle alternators. I never had trouble like you described. Sometimes I had to use some force and a hammer but never had to use heat or solvent or anything.
You just had bad luck me thinks
-Olaf

 

[swbluto]

I have rewound roughly 100+ industrial outrunners from copymachines, laserprinters and even motorcycle alternators. I never had trouble like you described. Sometimes I had to use some force and a hammer but never had to use heat or solvent or anything.
You just had bad luck me thinks
-Olaf

I'm thinking that past complaints of loose windings and the exceedingly thin wire they use that easily gets loose led them to coat the windings with some kind of varnish/glue to "keep it tight". Somehow, the "industrial standard" doesn't consist of that, likely for rewinding capability or lack of those particular problems, methinks.