Question

A single phase semi-converter connected to 230 V, 50 Hz source is feeding a highly inductive load R=10 $\Omega$, L= 3 mH. The load current is ripple free. For the firing angle of ${30}^0$, the reactive power input is

Answer 1

Average output voltage,

$V_0=\frac{V_m}{\pi }(1+\cos \alpha )$

$=\frac{230\sqrt{2}}{\pi }[1+\cos {30}^0]=193.20V$

$I_0=\frac{V_0}{R}=\frac{193.20}{10}=19.32A$

Reactive power
$=V_0{I}_0\tan \left(\frac{\alpha }{2}\right)=1kVAR$