E-Bike System

[BrianG]

I was thinking about the multi-speed concept and wondered why an "electronic transmission" couldn't be used?

Option 1: Have separate wires for both ends of each motor coil (similar to how the old hi-amp LMTs were set up). Then, the ESC could electrically configure the motor for Y wind at low speed and D wind for higher speeds. The switchover would result in a 1.73x change in kv.

Option 2: Have the motor wound in whatever way it is (probably Y), but bring out a couple extra "tap" for each coil. Then, the ESC could power individual taps, resulting in different kvs.

Either way, more wires will need to be brought out of the motor. This increases weight, but that should be offset by the gains from the mechanical friction and weight of an actual transmission. Also, the ESC would be more complex.