Motor Modifications for more RPM
It is well-known that a certain contributor to this forum modofies EVT hub motors to provide 50 mph/80kph speeds. This involves increasing the free-spinning RPM's from about 750 RPM to about 1100-1200 RPM. He dees not seem to be willing to offer any technical information on this modification.
Can someone with some background in electric motor design provide a general idea how this is being accomplished? Does this involve new windings, commutation timing, or a combination of these?
Thanks in advance for the help.
Changing the timing trades a slight speed increase for a reduction in torque and efficiency. The most effective way to raise RPM is to rewind the motor with fewer turns of thicker wire.
But with fewer turns of wire, it will raise RPM of the motor, but does it NOT lose torque ?? I mean I would like my Emax scooter to be faster using the stock 48volts, but if it does not have the torque to haul my 200+pounds around then it is no use for me.
The torque constant (torque per amp) will be lower, so you just run more current. Efficiency ends up about the same since the shorter, thicker wire has less resistance. If you don't like the concept then run higher voltage. There's always a trade off.