Variable ac motor driver

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Joined: Mon Jul 02, 2018 1:08 am

Variable ac motor driver

Post by spadekevin » Sun Jul 15, 2018 7:20 am


Ive been trying to give an ac motor variable speeds using an rpi, with a dc motor I can use pulse width modulation but pwm doesn't seem to work with the ac motors, or certainly not these with a starting/running capacitor. however applying a resistance to the electrical feed does allow for variable speeds. with the pwm I could see and hear the fan speeding up and slowing down irrationally, I was using python. can it be done or am I barking up the wrong tree? is anybody aware if you can control ac with pwm? or alternatively is anybody aware of some kind of potentiometer that I can control with the raspberry, or would it be a case of just having set resistances then selecting the resistance used through gpio set up?

Please help.

I didn't find the right solution from the Internet.

References:- ... p?t=134100
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