Multiple motor speed control with a single triac

Thread Starter


Joined Sep 4, 2012
I have a requirement where I have to control the speed of 10 motors. When I mean speed, I do not mean RPM, generally all motors have to be fed the same voltage (phase angle control). The motors are 230V AC single phase motors. The speed of the motors need to be increased or decreased using a electronic controller (no varistor). All the motors need to run at the same speed. I am considering phase angle voltage control to control the speed of the motors.

Each motor consumes maximum 2A current.

I have identified BTA24 Triac which supports 25A load current. This is a snubber less triac.

My first question is whether it will be possible to control all the 10 motors using a single triac. i.e phase angle control using 1 triac and connect all the motors to one of the terminals of the triac.

My second question relates to snubber.

I have a micro controller which will drive this triac. There will be an randhom phase opto coupler between the micro controller port and the triac.

The triac I am using is snubberless. In many of the circuits I have seen, there are two snubbers, one is for the triac and another for the optocoupler.

In my case, the triac is snubber less, does it mean the opto coupler needs one? I will be using moc3023 as the triac driver.


Joined Sep 9, 2010
When I mean speed, I do not mean RPM...
You lost me with that statement. Do you mean you need to control the SYNCH of ten motors, in addition to them obviously being all at the same (and variable) rpm?

So for instance it is not acceptable for one motor to be at 1000 rpm and another at 1000.5?

Thread Starter


Joined Sep 4, 2012
Yes you understood me correct, but may be I should clarify.

I am not trying to control the RPM on all 10 motors. Each of them may have their own RPM at a given voltage. As you mentioned 1000RPM in one and slightly off on the others

I am only controling the voltage/power supplied to them by phase angle.