Mechanical PWM control
 

Hi folks,

Something just hit me...

PWM motor control is easy to build for small motors, and a real $$$ PITA to build for large motors, for reasons of current and voltage handling ability, cooling and other issues. I was just thinking about this, and then remembered something..

Back in the '60s an early pulse proportional radio control system used a mechanical pulse width modulation technique...

It consisted of a cylinder, rotated by a small electric motor. This cylinder had a copper contact surface that went from 0% of the circumference at one end to 100% at the other end, and by operating a slider up and down the cylinder as it rotated, one could vary the pulsewidth.

Given that there are numerous options these days for small high efficiency motors that could drive such a device, it would appear that one could construct one that was as efficient as the best high power semiconductor controls.

Just thought I'd throw that out in case the thought of requiring $2000 worth of electronics was putting anyone off EVing.

Road Warrior

Damn, just realised I'm behind the times with the pricing on units that handle a decent amount of power.... last time I looked a year or so ago, they were $$$, but these don't look too bad at all...
https://motor-control.motcontroller.com/