Can i use a light dimmer to control a motor speed?

Question

the dimmer is for 250 vac and i am asking if i can put it between the dc motor and a 12v dc supply

Answer 1

Don't put it between your 12V supply and motor

Put it between your wall outlet and the 12V supply.  Then connect the supply directly to the motor.

I've done this as a cheap way of getting variable low DC voltage from an unregulated supply..

Oh, and since you"ll be dealing with high voltage.  

Put the dimmer in a box.  Like the ones for electrical wiring.  A single gang utility box is fine and cheap.  Or there are prettier and more expensive ones if you prefer.  You can pass the wires through the knockouts,(no drilling needed) And clamp them with a Romex connector.  Get a cover plate too.

Any electrical or hardware store will be able to help.

ALWAYS work with the power disconnected, AND check everything twice before you plug it in.

Good Luck in what we Hams call Homebrewing

Answer 2

YOU CAN CONTROL AN  AC MOTOR BUT LIMIT TO 300 WATTS (OR VA),BECAUSE THE HEAT SINK IN A DIMMER IS VERY SMALL EVEN IT SAID IT CAN GO UP TO 600 WATTS. YOU NEED TO ADD A 0.1 uf capacitor at least rates at 400 volts and a 100 ohm resistor at 1 watt  to make the control more smoothly to control motor speed. Join the capacitor and resistor in series then connect one side to the dimmer output where connecting the motor. Other side connects to the neutral.

IT SHALL NOT WORK ON DC MOTOR BECAUSE DIMMER IS MAKE OF TRIAC. IT CONTORLS AC POWER,AT DC,IT SHALL TURN INTO A STAY ON SWITCH

To control a 12 volts motor speed is quite simple,just add a variable voltage control to your 12 volts power supply. Therefore you can change the voltage from 0 to 12 volts,the motor speed can be controlled by vary the voltage.

The most simple way is series the 12 volts power supply with a variable resistor,need 10 watts or more,choose 100 ohm variable to start,depending on the motor that you want to control.

Answer 3

I've done this as a HS project. The Light Dimer controls a step down Xfmr (120Vac / 12Vac) which feeds a Diode Bridge Rectifier creating the DC output you want.

Using Pin = Pout

The power of the 12Vdc moter can then be calculated back to the 120Vac input.

i.e. 12Vdc mtr @ 10amps = 120Watts then Pin = 120Watts = 1amp x 120Vac.

There's some losses here, but in general this will get you what you want.

Select the step down Xfmr to handle the 10amps, 12V as well as the Diodes.

Answer 4

I have used a light dimmer on an HO gage train track.  Run the dimmer into a 120v to 24v center tap transformer (12 DC out of rectifier).  The transformer I had had two diodes mounted to the chassis for full wave rectification.  I ran the DC to a double pole double throw center off switch to control direction. Add a capacitor to the DC  to smooth out the ripple which made for a more realistic operation.  I could double head two engines with no problem.  Had a lot of fun with it.  I also used a light dimmer to control the heat of a 200 watt soldering iron when I put together a tiffany lamp.

Hope this helps.

D.Bumstead

Answer 5

The dimmer of course allows through a varying amount of current, so in theory yes.

It is a bit problematic that it is designed for AC though. You should certainly try it out. My sense is that it should work anyways.

Answer 6

Lamp dimmers work on 120 or 240 volts AC only, not on DC.

.