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View Full Version : Rewound motor cant handle 4S anymore, why?


alcarafa
10-08-2010, 07:34 PM
I've rewound a turnigy 42/40 - 800 kv motor http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8487 (http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8487)
I used AWG 20 wire with same 13 turns it was before, problem is motor cant handle 4S lipo it gets hot as hell, I tested motor with APC 13/4, 80 amps ESC and 3500 mah 4S lipo.

Tried same propeller and ESC with 3S 2700 mah lipo, it works fine without getting hot :) wattmeter shows 37.7 amps and 438 watts with 3S lipo, why cant motor handle 14.8 volts anymore ? :confused:

kyleservicetech
10-08-2010, 10:44 PM
I've rewound a turnigy 42/40 - 800 kv motor http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8487 (http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8487)
I used AWG 20 wire with same 13 turns it was before, problem is motor cant handle 4S lipo it gets hot as hell, I tested motor with APC 13/4, 80 amps ESC and 3500 mah 4S lipo.

Tried same propeller and ESC with 3S 2700 mah lipo, it works fine without getting hot :) wattmeter shows 37.7 amps and 438 watts with 3S lipo, why cant motor handle 14.8 volts anymore ? :confused:

Might be you've got a shorted winding? Take a look:
http://www.wattflyer.com/forums/showthread.php?t=35216

Also, you could have one winding reversed. A reversed winding will show up with the test below:
Third:
Short circuit all three wires together directly at the ends of the motor windings. Then SLOWLY wind up the variable speed drill while holding the stationary part. Be careful, you will have considerable drag where the motor will try to twist out of your hands. This drag will be very even, with little variation, and no "Chugging". As a comparison, only short two wires, and try again. This test will be very obviously much less smooth than when all three wires are shorted. Don't run the motor more than 5 or 10 seconds, as the windings will get warm doing this. (Don't use jumper wires, we are generating 20-30 Amperes or more of current at very low voltage, jumper wires won't work.)

alcarafa
10-09-2010, 07:24 AM
Thanks for your reply, will try as you say and will post results here.