How to check motor winds
 

What is needed & how do check to see if the motor in our local classes are actually the proper turns for the class?

I have seen them check motor at national events but never stopped & asked.

How do I check & what are the #'s I should be looking for in 25.5, 21.5 & 17.5 classes?

Thanks,
Joe

You'll need to find the minimum stator resistance in the ROAR rules, I don't know them offhand.

All you need is something that can (accurately!) check resistance. A multimeter won't do, and I'm not sure what the actual tool is called.

At the moment ROAR specifies minimum terminal resistance only for 25.5 motors: 101 milliohms at 25C. Reasonable numbers for the other winds would be 64.9 milliohms for 21.5, 42 milliohms for 17.5, and 25 milliohms for 13.5. All of these are also at 25C.

You'll need an accurate milliohmmeter, which isn't cheap, and a thermometer. If speed of measurement is not a priority, here's a less expensive way to do the test:
http://www.rctech.net/forum/radio-el...l#post14329133