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Powering tools with Washing Machine Motors

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Bongodrummer

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I keep finding working washing machine motors - always the brushed universal type, which seem to be everywhere. Has anyone else got example implementations of these motors on workshop tools? I have experimented with various speed control methods (and they DO need controlling - if hooked up to mains, unregulated their no-load speed is enough to damage the motors bearings, armature, and in worst case fly apart - don't stand too close!) for a number of DIY tools.

I have experimented making basic triac circuit variants in a lathe, disc sander and pillar drill, but in my latest project, a multipurpose rotary machine (mainly used as a green sand muller http://machine.construction/rotary_tool ), I had a crack at making and understanding an Arduino based, closed loop control circuit. While I found it theoretically straightforward - PID algorithm takes in Motors actual RPM, compares it to our desired set RPM, and triggers the triac accordingly - the implementation is proving tricky.

Here's a video of the speed control circuits - might be usefull for some folks. https://youtu.be/xI6CF2nYf_g?list=PL95E ... mEvzn5y3Nf

I have it working relatively well in RPM ranges from 1500 to 4000 (I don't need it to go higher, but doubt that would be a problem) :D . But below that speed I am struggling to get consistent performance from the motor/controller... Am getting phantom triac triggering etc. It's a long shot but anyone have experience fiddling with the tuning parameters of PID to give good performance at low speed?
 

Myfordman

AKA 9Fingers
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Even once you have the speed under control, they are nearly always open frame motors and need protection from fingers and flying debris.
They are also not contiuously rated at full power. In normal use they run slowly most of the time at low power and hell for leather once or twice on the spin cycle before resting.
Based on over 50 years of tinkering with machinery and motors, TEFC 3 phase induction motors plus inverter control is the only sensible way to go.
 
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