Foot Pedal Motor Speed Contol

[lmartin]

I have a 120 Volt AC-DC, 8 ampere motor rated at 25-60 Hz. I want to control this motor speed with a foot pedal.
Is this possible, and if so, what components do I need to make this happen?

 

[jraef]

Assuming from the description that it is a "universal motor", then just varying the voltage going to it will vary the speed. That is what is used in your variable speed drill motor for example. So what you need is a foot pedal with a potentiometer capable of handling at least 8A. 8A at 120V is 960watts, thats a lot of power for a potentiometer direct. I would go for as much more as I could find and afford though.

But that may be very difficult to find, I don't know of any. Most foot pedal pots I see now are just used as signals for something else, so they are only 2watts or so. In that case then you would need to take that 2W signal into a variable voltage controller to amplify it to the motor current rating.

Search for "linemaster variorum potentiometer" for the foot pedal, then search for "AC variable voltage controller" for the other part. You will want a minimum 8A 120VAC voltage controller that can accept an analog input of a potentiometer or voltage such as 0-10VDC, and that analog signal is what you put through the foot pedal.

"Will work for (the memory of) salami"

 

[Compositepro]

Foot pedal controls for universal motors is fairly common for sewing machines and die grinders.

http://www.mcmaster.com/#die-grinders/=n2sez9

 

[itsmoked]

Perhaps you can use a dimmer to control the motor then mechanical-it into the footpedal. You would definitely want to use the type dimmer that states "controls motors or inductive loads". That's about a quarter of the ones out there.

You could wire it up and try it by hand before working it into a footpedal.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

"Dimmer" is another name for a potentiometer. The type for sewing machines are nowhere near capable of 8A / 960W, the only ones I saw were rated 150W at the most, many are 15W and for die grinders they get to maybe 250W. That was my point. 960W is just too much power to run it directly.

"Will work for (the memory of) salami"

 

[Skogsgurra]

Potters sometimes use a Variac with spring return coupled to a foot pedal or a knee-operated lever to control their turntables. Not rocket science, but works well and no complications.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Jeff, jeff, jeff. "Dimmers" are almost never potentiometers. I was referring to what you'd get in any hardware store you go into when you ask for a "dimmer". You'll never get a pot, in that case you'll get an SCR based controller, many of which are rated for motors like Casablanca fans. You can easily find 1000Watt+ units rated for fans. Any Lowes has them.

Keith Cress
kcress -

http://www.flaminsystems.com