A three-phase half-wave controlled converter is fed from a 3-phase, 400 V source and is connected to a load which takes a constant current of 36 A. Find, the value of average output voltage and average current rating of SCR for a firing angle of 30°.

To find the average output voltage and the average current rating of the SCR for a three-phase half-wave controlled converter, we can use the formulas specific to this type of converter.

1. Average Output Voltage (V_avg):

For a three-phase half-wave controlled rectifier, the average output voltage can be calculated using the formula:

[

V_{avg} = frac{3 sqrt{3}}{pi} V_{s} cos(alpha)

]

Where:

– ( V_{s} ) is the line-to-line voltage.

– ( alpha ) is the firing angle.

Given that ( V_{s} = 400 , V ) and ( alpha = 30^circ ):

– First, convert ( alpha ) to radians (if necessary):

[

alpha = 30^circ = frac{pi}{6} , text{radians}

]

– Now, substituting the values:

[

V_{avg} = frac{3 sqrt{3}}{pi} times 400 times cos(30^circ)

]

[

cos(30^circ) = frac{sqrt{3}}{2}

]

[

V_{avg} = frac{3 sqrt{3}}{pi} times