Leon wrote:
wrote in message
ups.com...
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


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.


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