Control pump motor speed??

[cruzmisl]

Hi All,
With some people pushing 2 speed pumps for energy efficiency would it be possible to put a single speed pump on a rheostat or electronic dimmer (for motors) to control the pump speed or would this torch the motor.?
Thanks,
J.

[Poconos]

Pump motors are induction type. Under load you can't really control the speed with a rheostat or dimmer. Under light load you can but it isn't recommended. A rheostat is just a variable resistor in series with the motor. Maybe another term is Variac which is a variable transformer where the output voltage is adjustable. No resistance element involved. A dimmer is a dual mode triac, solid state device that triggers on a controlled part of the AC cycle. They aren't compatable with motors or fluorescent lights. Multiple speed motors have a separate winding that is switched in for the low speed.
Al