Replies

1. 
   JohnWW | Feb 20, 2006 03:55am | #1

   If you have a typical shop grinder with a single phase induction motor, it can't be slowed down with a speed control, the basic physics of how an induction motor works makes it impossible to change their speed easily.  If your grinder is basically just a motor with a grinding wheel hung on either end, the motor is an induction type and it will only run at one preset speed. 

   If you have an industrial grade grinder with a three phase induction motor, you could hook it up to a device called an inverter which would allow speed control, but this can't be done on a single phase motor.  Inverters are getting cheaper, but even the smallest ones cost several hundred dollars.

   The inexpensive speed controls, like the one Rockler sells, are for universal motors, which are the small, high speed motors typically used only in portable power tools.

   John White, Shop Manager, Fine Woodworking Magazine

2. 
   JohnWW | Feb 20, 2006 08:33pm | #2

   You're welcome.

   John W.