Re: Mini-drill; Speed Controller Problem
I currently use a 12V battery charger which is adequate to drive a DC motor running a coil winder.
I did an experiment with a rectified but not smoothed supply controlled by an SCR. An op-amp compared the motor voltage with an adjustable voltage. If the motor back EMF voltage was too low, the the SCR was triggered. Thus the speed was measured 100 times a second and corrected as necessary. I found that this was not necessary when winding thin wire so has been put in the round tuit pile. A battery charger and Variac is used at present.
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