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Triac based AC motor speed controller

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maxim10373

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Hi friends
According to this diagram speed reducing zero to maximum.
but voltage fluctuating (flickering if connect a BULB)on output.
is this method possible to drive a triac ?


regards
maxim
 

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I have answered this same question several times in he past, but once again, here it goes:

For TRIACS, you require phase control, not PWM control.

Phase control is in essence a monostable which is triggered by the AC waveform's zero crossing. In other words, synchronized, which your astable circui is not.

Since the firing phase angle is delayed from the zero crossing, you also cannot utilize an optotriac which only fires at or very close to the zero crossing. You require a random firing optotriac.
 
this circuit cannot be used for speed control
you can use it just for turning on and off because moc3061 is a zero crossing opto-triac it gets ON only at the zero cross of the mains even if the excitation pulse comes sooner so it cannot control the firing angle that is needed to speed control.
 
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