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Conduction Angle in SCR Single Phase Rectifiers

  1. Nov 2, 2013 #1
    Hi all,

    When considering a half wave SCR rectifier (single phase) with an RL load, the term θ (conductive angle) appears in equations relating to the performance of the circuit.

    In terms what is physically happening in the circuit, what does θ actually represent?

    Attached Files:

  2. jcsd
  3. Nov 2, 2013 #2


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    considering a single period to be 0 to 360 degrees, the scr turns on at the conduction angle.
  4. Nov 2, 2013 #3
    I thought the SCR is turned on at the firing angle (α).
  5. Nov 2, 2013 #4
  6. Nov 2, 2013 #5


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    OK, my bad. Firing angle is angle at which it starts conducting, conduction angle is angle over which it conducts.

    But theta in the above circuit is the voltage/current phase angle caused by the RL circuit. The SCR is fired at α, but conducts beyond ∏ -α because of the inductor field collapsing, represented by theta. So it continues to conduct until ∏ + theta.
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