Question

A 3-phase full wave controlled converter is fed from 3-phase 400V, 50Hz source and connected to highly inductive load with load resistance of 10$\Omega$. If the firing angle delay is ${45}^0$, the rms value of source current is ______A.

• A. 31.18

Answer 1

The correct option is A 31.18
$\because \alpha <{60}^0$

Average output voltage, $V_0=\frac{3V_{mL}}{\pi }\cos \alpha$

$=\frac{3\times 400\times \sqrt{2}}{\pi }\cos {45}^o$

$V_0=381.97V$

$I_0=\frac{V_0}{R}=\frac{381.97}{10}=38.19A$

Rms value of source current $I_s$ is,

$I_s=\sqrt{\frac{2}{3}}{I}_0=\sqrt{\frac{2}{3}}\times 38.19=31.18A$