Triac Motor Speed Control Arduino

In which single phase induction motor speed control by using triac and 555 timer.

Triac motor speed control arduino.

So far we have shown how to control on off status of an ac powered appliance with ibm watson iot that guide is important to use http s post request instead of using mqtt. Int triac 6. Http post and mqtt has difference of use case in this present article we only restrict ourselves to discussions around esp32 arduino ac motor speed control module and circuit. Fig 3 shows the triac firing circuit.

Yet in spite of the simplicity of the circuit the software needed was a bit complicated as it needed to keep track of the zero crossing of the ac signal then keep track of the time and then finally open the triac. Thus the applied voltage to induction motor stator terminals is controlled by triac and its gate pulses 2. This ac motor speed controller circuit is working based on the triac and diac. The devices running on dc voltage are usually controlled by changing logic at gpio pins for switching control or by pwm for operational control.

Pulses synchronized to the ac sinewave half cycle are output from arduino digital pin 5 to the led in the moc3011 which also serves to isolate the high voltage ac from the low voltage components. Simple ac motor speed control circuit using bt136 triac. Diac triac phase angle control circuit it applies chopped ac waveform to motor and varies speed of ac motor. The complete control circuitry depends on only one parameter i e voltage.

Without it the motor will spin at it s maximum 15000 19000 rpm. As the width of ic555 output pulse is varied using potentiometer the firing angle of triac. It s too much for wood lathe. You can use household equipment like a drilling machine to control the rotating speed of it.

We know that torque developed is proportional to square of the voltage. To control the motor peed we could use a scr voltage regulator but at low rpm the motor will be weak with no torque. So the circuit varies speed of ac motor by changing firing angle of triac by applying pwm generated using ic555 connected in monostable mode. That proved to be a very popular design.

Next inside setup function declare the triac pin as output as pwm output will be generated through this pin. Only one thing left the motor speed controller. A lot of arduino projects involve controlling devices running on dc voltage. And the variable speed val is declared to store the value of speed step.

The moc3011 opto coupler uses a photo triac as opposed to a transistor. There are times when devices running on ac current also needs to be controlled by the microcontroller for switching control the ac appliances are usually interfaced to.