SteveC wrote:
I have a 1 hp electric motor (110 volt) and I want to be able to control the
speed from slow to fast and in small increments.

What basically do I need?
Or where will I find the answer.
Thanks.



First you should tell us what type of motor you are asking about.

And, what "slow" and "fast" mean in real RPM numbers.

If it's a "universal" motor (One with brushes in it.) you could vary its
speed with a solid state speed controller, a device which is similar to
a solid state lamp dimmer, but may cost a bit more. That'll work, but
the set speed will vary somewhat if the load changes.

http://www.harborfreight.com/cpi/cta...emnumber=43060

If it's an induction motor, about the only way you can manipulate its
speed electrically is with a variable frequency converter. They're not
cheap, and they won't give you an extremely wide range of speeds either.

http://en.wikipedia.org/wiki/Variable-frequency_drive

If its an induction motor I think Speedy Jim's suggestion of using a
variable speed pully system, with perhaps a secondary pair of stepped
pulleys to give you a wider range would be a fine way to go,
particularly if you need to get near full power over a wide range of
near constant speeds.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.