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[on:]

Good day to one and all,

Got hold of a big DC motor from a running machine (treadmill) and I'm just looking for some suggestions from the old hive mind as to the correct way to go about speed controlling it with the Arduino Uno.

Eventually I want to transplant this into my wood turning lathe to get rid of the constant speed capacitor start rubbish that is in there at the moment.

I'm okay with the programming side of things and I am able to output into the real world on the small scale, for example, 5v DC motors and servos.

Would I have to go the MOSFET route or could I simply get away with using an appropriately rated SSR, triggered by the PWM output of the Arduino to "chop up" a 180V DC source?

The 180v DC would be coming from a simple transformed mains - rectified and smoothed.

Any help or suggestions would be gratefully appreciated.

Thanks muchly.

[Reply #1 on:]

Would I have to go the MOSFET route or could I simply get away with using an appropriately rated SSR, triggered by the PWM output of the Arduino to "chop up" a 180V DC source?

Most SSR are for AC voltage only as they use SCRs or Triacs that won't work with DC voltage switching.

Going with logic level mosfets (if you can find some rated for such high voltage) would be the simplist method and then the arduino could use a PWM output pin to vary the speed of the motor using analogWrite() statements.

The 180v DC would be coming from a simple transformed mains - rectified and smoothed.

Be sure your AC outlet, circuit branch wiring and panel circuit breaker is rated for this current.

Lefty

[Reply #2 on:]

In the 180V*12A=2160W domain I'd stay away from building your own stuff and use an off-the-shelf motor driver. Either look up the big industrial guys (Kollmorgen? Danaher? Anaheim?) or the heavy-duty battle-bots crowd (though I don't know how they'd use 180V).

It is a HUGE jump from the world of 5VDC motors and servos to what you are contemplating.

--
The Gadget Shield: accelerometer, RGB LED, IR transmit/receive, speaker, microphone, light sensor, potentiometer, pushbuttons

[Reply #3 on:]

I would agree, high voltage high current MOSFET switching is fraught with problrms - too much energy flying around, one mistake and they explode, potentially taking all the logic circuits too - protection circuitry is essential, and thats the sort of voltage where IGBTs take over anyway.

[Reply #4 on:]

The first place I'd look would be how the treadmill controlled the motor. How does it vary the speed of the motor? At the Y the treadmills appear to plug into a 120vac outlet strip on the floor, so the power requirements apparently aren't terribly large.