Have somebody seen my magic smoke?

A little while since the last post, this is maybe old information if you have read my posts on Endless Sphere or the Swedish Electronics Forum. We played around for the whole weekend with the moped until the motor got enough. My guess is that several hard accelerations during a short period of time heated the stator enough for the insulation to melt.

The black insides of a BLDC motor
The black insides of a BLDC motor

Not pretty! I’m afraid I’ll have to torment my hands with another rewind. A member on SEF is good enough to donate a large roll of 1,5 x 2,5 mm flat copper wire to me which I will use for the rewind. I have three different actions to prevent this from happening again.

  • Increase the gear ratio. Less torque on the motor means less current.
  • Increase kv, one less turn of copper wire will increase kv to match the higher gear ration and reduce the resistance. It will also leave more room for air to flow through the motor
  • Forced cooling, I’ll put a fan in one end of the motor to force more air through.

I’ve also ordered a spare motor from china. The 80-100 is very hard to get nowdays, but I found a 80-85 motor with the same mounting profile and axle. But i’ll keep a close watch on the stock of the 80-100 motor.

2 thoughts on “Have somebody seen my magic smoke?”

    1. I’ll answer in English since most people reading this will not understand Swedish. Your question is what I think of the 80-100 size bldc motor sold by leaderhobby.
      I’ve actually ordered the 80-85 version of this motor from leaderhobby, would have ordered the 80-100 but that one was out of stock at the moment. I guess that the motor are made in the same factory as the one Hobby King sold. The measurements are exactly the same, and the quality is also the same. You could definitely use that one to power a bicycle or moped. Just be sure to use a higher motor rpm and a lower gear ratio than I did to prevent the motor from going up in flames.

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