Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Universal Motor Speed Controll

Status
Not open for further replies.

tom_pay

Member
Hi All,

I have been trudging through the internet for almost a few hours now looking for how to control the speed of a universal motor.

It is not the actual circuit I am looking for it is just what I have to do. Is it a frequency change, a voltage change or what?

Also does the rotor get wired in series to the stator?

Thanks in advance,

Tom
 
Hi Thanks For that,

Unfortunately the controller no good for my purpose, I live in a 240v area and the particular motor I want to use is also 240v.

So if I connect the stator in series with the rotor and a rheostat, should that give me speed control?

Thanks

Tom
 
Last edited:
I don't know how big your motor is but it may need a big rheostat. I think they take well to dimmers. Parallel connection.
 
Ok, The motor says 240v, 3A, so I guess a big rheostat would be required.

What, electronically, does a dimmer do? Is it just a PWM of the original sine wave?

So the rotor is wired in parallel to the stator.

Tom
 
AFAIK most (all ?) universal motors have their rotor and stator windings in series (check with Wikipedia). I'm pretty sure my mains-powered drill has a universal motor, and its speed control is a simple phase-angle control (similar to a light dimmer).
 
It is not the actual circuit I am looking for it is just what I have to do. Is it a frequency change, a voltage change or what?
Also does the rotor get wired in series to the stator?

Average of the absolute voltage.. or RMS voltage. If you run it from AC mains power, you can try to connect a diode in series with the motor. The diode cuts away half the power (half wave rectification) and the speed should be about half also. You can google for dimmer circuits that can control the average voltage more precisely. http://www.techlib.com/electronics/power_control.htm

Usually the rotor and stator are wired in series.
 
Last edited:
you can try to connect a diode in series with the motor.
I wouldn't recommend it. Inductive loads don't like DC. I tried that years ago with a motor and blew a winding.
 
I wouldn't recommend it. Inductive loads don't like DC. I tried that years ago with a motor and blew a winding.

Universal motors can run on DC (the stator is connected in series with the rotor). Actually they have better efficiency when driven with DC because AC causes eddy currents in the stator. Stalling the motor can blow it up, but that is a problem with all DC motors.
 
Last edited:
Ok, So basically a PWM of the AC, or rectified AC, will get it going.

So in theory would the 240 VAC work if I just hooked it up the the 12VDC car battery and go 1 / 24 times as fast?

Also, I'm trying to this project on the cheap!!, but would a simple in wall light dimmer from the hardware store work? Or would it be too little?

Thanks heaps,

Tom
 
Last edited:
So in theory would the 240 VAC work if I just hooked it up the the 12VDC car battery and go 1 / 24 times as fast?

I'm not sure if the speed is linearly proportional to the voltage, but with 12 VDC the speed should be a lot less than with 240 VAC.

Also, I'm trying to this project on the cheap!!, but would a simple in wall light dimmer from the hardware store work? Or would it be too little?

Maybe, I have no idea how big and powerful your motor is.
 
I tried it with the car battery this morning and it runs just a bit too fast but it is hasn't got enough torque.

If I were to use a PWM of a much higher voltage would this give it more torque?

Thanks so much,

Tom
 
If I were to use a PWM of a much higher voltage would this give it more torque?
Yes it would.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top