If you frequent any CNC Forums out on the ‘web you’ll find that these Chinese 3020 CNC routers are generally well received. It is also common opinion that the control electronics leave something to be desired. [Peter]‘s feelings were no different. He set out to make some improvements to his machine’s electronics such as fixing a failed power supply and adding PWM spindle control and limit switches.
[Peter] determined that the transformer used in the power supply was putting out more voltage from the secondary coil than the rest of the components could handle. Instead of replacing the transformer with another transformer, two switch mode power supplies were purchased. One powers the spindle and the other is for the stepper motors. So he wasn’t guessing at the required amperage output of the power supplies, [Peter] measured the in-operation current draw for both the steppers and spindle motor.