How to wire a variable speed drill press

[alex.colic]

Hi,

I was visiting a wood working shop and I noticed that they had rewired one of their drill presses to run the motor at a variable rate. It looked like the original 1HP motor connected to an off switch along with a variable speed switch. The speed changed by turning the switch clockwise and counter clock wise.

This sounds like a great idea and speeds up work by not having to keep changing the belt location on the pulleys.

Could someone please point out how to wire a switch and motor to achieve this? Any pros/cons that I would need to know.

Thanks

Alex

[Leon]

That may only work with a universal motor vs. the typical induction motor. I tried that out with a speed control on mine and the start and or run capacitors would kick in and essentially it became an uncontrollable variable speed at certain voltages. Other than that I was only able to actually reduce the speed about 10% from top speed.

[Hall Family]

This is correct. An induction motor will be ruined by constantly trying to control rpms via voltage reduction. You need a universal motor as stated above typically as found in a washing machine to do what you want. Then you could use a router speed control, dimmer control, or just about any rheostatic device that has the current handling capabilities of the motor your trying to replace. Be alert to the phasing of the motor. There is a BIG difference between 3phase and single phase motors.

Troy

[support]

I would check with the manufacturer and while they would have a "that would void your warranty" a tech there might be nice enough to give you "off the record" advice.

Some types of motors it would ruin, other types it might work just fine.

Steve

[lwasserm]

Motor speed control is not practical on a single phase induction motor such as is commonly found on a drill press.