13-06-2026, 07:35 AM
(12-06-2026, 07:37 AM)decowoodie Wrote: The only problem with variacs is they dont compensate for when the motor's under load, whereas an electronic DC controller continually senses the back EMF from the motor and adjusts the voltage to keep it more constant. If you mainly take small cuts I dont suppose it matters.
I have a small Axminster milling machine in which the control board was replaced and then failed a bit later. It uses a DC motor, so I hashed up a simple open-loop thyristor controller. In practice, I find the lack of self-control via back EMF is actually an advantage for light work, as it limits any 'grabbing' effect. I do have a big blighter for serious cutting...
