The motor I have chosen to be the spindle in my CNC router table is a 1/4" 30,000 RPM, 3A Makita Die Grinder model 906H. It has brushes, and I think motors with brushes will work with a reostat to control motor speed.
My question is, will this motor work with this variable speed control board from CNC2PC ? http://www.cnc4pc.com/Variable_Speed_Control_Board.htm
This circuit claims it is a frequency to analogue converter for driving the +- or + 10vdc that is common on 3phase VFD's, so in and of itself it is not much good for you for this motor unless you had some kind of motor controller that required an analogue signal.
But it does not appear to be opto-isolated so it would not be safe to use with a Universal motor controller that had no isolation, which is common for triac type variable speed controls.
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