How does this circuit work

Discussion in 'General Electronics Chat' started by Mad Professor, Jan 1, 2011.

  1. Mad Professor

    Thread Starter Active Member

    Apr 15, 2009
    133
    1
    Good Day All.

    Can someone please explain to me how the this circuit works?

    [​IMG]
    The above circuit is from my Power Performance FMTC1020R Router.

    It is used to control the motor speed from 11,500-34,000rpm.

    I am used to dealing with DC voltage, and using PWM to control motor speeds.

    But when it comes to AC, I don't know a grate deal.

    I have a very healthy respect for mains voltages.

    If someone could try and explain to me how the above circuit works I would be very gratefull.

    Best Regards.
     
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    Looks to me as a simple modification of a common light dimmer circuit.

    D1 would be a diac though so the symbol is wrong.

    SW1 would enable full on, VR2 would be the control and VR1 would be a trimmer adjustment.
     
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