Question

A single phase fully controlled bridge rectifier is operated from 240 V, 50 Hz ac mains with firing angle ${30}^0$. Load draws a continuous and ripple free current of 12 A. Then which of the following is correct ?

• A. Average output voltage is 187.12 V
• B. Rms value of source current is 6 A.
• C. Reactive power drawn from the supply is 1296 kVAR.
• D. Real power drawn from the supply is 3245.4 W.

Answer 1

The correct option is A Average output voltage is 187.12 V

Average output voltage,

$V_0=\frac{2V_m}{\pi }\cos \alpha =\frac{2\sqrt{2}\times 240}{\pi }\cos {30}^0=187.127V$

Load current given, $I_0=12A$

${\left(I_s\right)}_{rms}=I_0=12A$

Reactive power drawn $=V_0{I}_0\tan \alpha =187.127\times 12\times \tan {30}^0$
= 1.29 kVAR

Real power drawn = $V_0{I}_0=2245.5W$