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Old Sep 24, 2012, 08:59 AM
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Jack
USA, ME, Ellsworth
Joined May 2008
18,094 Posts
Quote:
Originally Posted by vinnieg View Post
..<snip>...

I just rewound a 19 gram motor, also 12N16P and an ABC wind, my smallest ever rewind. I did that with three strands of 32 AWG.

On your 19 gram motor, why did you use 3 strands of 32 AWG wire instead of a single strand of something bigger ?

-vinnie
I had read somewhere that the original wind on that was 3 strands of 0.2mm (32 AWG) wire but when I got the motor someone had already tried to rewind it with 24 AWG. That only had 8 or 9 turns and was very disorderly so I started over.

So I decided to see how multiple strand winding goes and tried three x 32 AWG because I had that wire. The original amount of surface area would have been 3 x 32 AWG or 0.096 mm2. That would be a little less than one strand of 27.5 AWG or so and I did not have any of that.

I tried a test wind with some 26 AWG, also looking for a higher turn count to drop the Kv, and that ran out of room too soon too. so I tried the 3 x 32.

As far as the mechanics of winding, I used my "3rd hand" accessory and that really made the multi strand process go very well. I laid the three strands in that side by side and flat, put a light sliding strain on the group, and that let me pull out a 12" or so length (strands were about 45" or so).

I had put a small dowel through the motor for handles and was able to keep the three strands flat and side by side and just roll the stator arms up the wire without any turning or twisting. The first layer went on as 5 turns with 15 strands laying side by side and absolutely flat. The second layer went on almost as neatly and when I got two layers on (10 turns) I decided to try that. I actually went to about 10-3/4 turns in the process of the transit to the next arm.

But looking at it now I think I could have gotten a third layer of turns on and now wish I had tried to do that. Oh well, next time...

I terminated it Wye, put some temporary bullets on it, and when I fired it up it was running beautifully. The bearings sounded like a washing machine full of rocks but that was another issue...

A no load showed a Kv of 2279 and it was pulling 1.02A. I tested it with my two smallest props and maybe it is OK at that Kv on 2S as I am not a compulsive full throttle flyer. I used a 3S A123 pack so the voltages are a little higher than a 2S LiPO would produce:

GWS HD EP-6030
32 seconds at full throttle
12,857 RPM 9.08V, 5.64A, 51W
temp rise 72F to 75F during run, peaked and holding steady at 75F

GWS RS EP-6050
22 seconds RPM limited to below audible fluttering
9,369 RPM, 8.84V 7.44A, 66W no temp taken, motor barely warm

I am happy with those numbers. 3.9W per gram on that slow fly prop and it is not overheating at full throttle, that cries out to be used. Like you, now I need to build something!

Jack
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Last edited by jackerbes; May 04, 2015 at 10:03 AM.
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