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View Full Version : What happens if you do this when winding?


shotgunsmitty
03-28-2009, 12:09 AM
I have a good old 24-08 bell motor....Towerpro, brushless outrunner, you know the one. It's a good workhorse, a budget motor.

I've rewound with two strands of 30awg wire and had a great running motor...through no fault of its own it ate some dirt (it had an airplane pushing it at the time) and the connecting wires broke very close to the stator. I don't really want to rewind this motor, it's not due yet, but I can't get the connectors close enough for some precision soldering.

Here's my question:

What would happen if I took one turn off the stator to give me enough room to resolder the connecting wires? I would take one turn off of each of the three wires, just for uniformity...but, I'll still have one additional turn on the other six.

Performance-wise, will I see any affect?
Safety-wise, could this damage my speed controller, battery, motor, or otherwise create an unsafe situation?
And, technically, what is going to happen when I put power to it?

Sparrowhawk
03-28-2009, 12:58 AM
I imagine you'd see some kV/RPM increase, along with some increased current, depending on how many turns were there in the first place. I have yet to rewind a motor, but have one on the shelf....waiting.

I'd just repair the motor and take some readings with an ammeter, or wattmeter if you have one. An IR prop tach is good too.

MustangMan
03-28-2009, 01:35 AM
I generally agree with Sparrowhawk.

You might also notice a little more vibration due to the slight imbalance in the winds. I expect it would run though.

Sparrowhawk
03-28-2009, 01:52 AM
I generally agree with Sparrowhawk.

You might also notice a little more vibration due to the slight imbalance in the winds. I expect it would run though.

Thanks, I didn't think about that. Hopefully 1 wind less is less than 10% of the total # of turns? The TP motors are around 14 turn (I think. More than 10 anyway).

shotgunsmitty
03-28-2009, 02:10 AM
So the magnetic fields could be offset enough to cause vibration due to 2/3 of the windings having slightly more winds.

Well, I'll definitely take readings with my wattsup and report my findings if anyone might be interested.

Sparrowhawk
03-28-2009, 02:17 AM
I would. I have another perfectly good EFlight 250 motor that has a wire broken off. I've been in touch with EFlight twice about it and they say it is unrepairable. It's just been sitting in a ziplock bag for 1.5 years.

shotgunsmitty
03-28-2009, 02:35 AM
Really? Why haven't you rewound it yet?
Send it my way!

Sparrowhawk
03-28-2009, 02:58 AM
Heh, it's sitting there, waiting...

It sure has lasted a long time though, no bad bearings or bent shafts yet! :D

fr4nk1yn
03-28-2009, 03:31 AM
HobbyCity motors come with uneven winds all the time (;
It'll run OK more than likely. But just OK.

As for that 250 it might have something to do with all the epoxy they jam on the wires.
Mine broke too an I had no way to fix it )':

Robbie d
05-07-2009, 04:47 AM
The epoxy and the wires themselves are not impervious to heat. If you strip the motor down to just the stator if possible, just use a heat gun until the epoxy is softened, then carefully cut it all off (gloves for heat protection. I have done this on other motors that have been 'potted'

Sparrowhawk
05-07-2009, 05:54 AM
The epoxy and the wires themselves are not impervious to heat. If you strip the motor down to just the stator if possible, just use a heat gun until the epoxy is softened, then carefully cut it all off (gloves for heat protection. I have done this on other motors that have been 'potted'

I'll try that 'next time'. I was able to save 90% of the insulation on the stator. It sure is a messy tenacious job to keep from damaging the insulation on it though.

ron_van_sommeren
05-07-2009, 03:27 PM
Hold statorpole in vise/clamp when pulling out the wires.