Conduction Angle in SCR Single Phase Rectifiers

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In a half wave SCR rectifier with an RL load, the conduction angle (θ) represents the duration over which the SCR conducts after being triggered at the firing angle (α). The SCR starts conducting at α but continues to conduct due to the collapsing inductor field, extending the conduction period to π + θ. The relationship between the firing angle and conduction angle is crucial for understanding circuit performance. The phase angle θ results from the voltage/current characteristics of the RL circuit. This distinction between firing angle and conduction angle is essential for accurate analysis of SCR behavior in rectifier applications.
buildingblocs
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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?
 

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considering a single period to be 0 to 360 degrees, the scr turns on at the conduction angle.
 
I thought the SCR is turned on at the firing angle (α).
 
Below are the formulas that I am referring to:
 

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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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