Electric Motor Speed Control

[SteveC]

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.

[Speedy Jim]

A variable speed pulley.

[Jeff Wisnia]

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.

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.

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

[---MIKE---]

You can't change the speed of an AC motor. The speed is governed by the

60 cycle current.

---MIKE---

[Ralph Mowery]

60 cycle current.

---MIKE---

While the speed is determined by the frequency , it is easy to change the speed. Just use an inverter such as:

Where I work we have 100's of them. They range from fractional horse power to over 100 HP motors.

For small motors , it may cost as much or more than the motor.

[ransley]

For a table fan I use an x10 controler and do it remotely, I dont know what type of motor the fan is but X10 might have something, but 1hp draws alot of current

[Mark Lloyd]

Most X10 modules do have limits on motor loads (as well as incandescent lights), but outlet modules are often rated 15A unconditional. If you don't want this installed in a wall, you can use an electrical box with a cord. I'm currently doing that for holiday lights (I use 4, on 4 different circuits).

[bud--]

A problem with variable frequency drives is they all (as far as I know) require a 3 phase motor (not likely for the OP's motor).

With a single phase motor one problem with controlling speed is the start winding will be reconnected at low speeds (most designs).

Universal/brush-type motor (as Jeff suggests)?