Question

A $3-\varphi$ full wave controlled converter is fed from $3-\varphi ,400V,50Hz$ source and connected to highly inductive load with load resistance of $12\Omega$. If the firing angle delay is $\alpha$ = 45°, the rms value of source current will be

• A. 24 A
• B. 26A
• C. 21.5A
• D. 23.5A

Answer 1

The correct option is B 26A

$Asfiringangle,\alpha <60°$

Average output voltage,

$V_0=\frac{3V_{ml}}{\pi }cos\alpha$

$=3\times \frac{400\times \sqrt{2}}{\pi }cos45°=381.97V$

$I_0=\frac{V_0}{R}=\frac{381.97}{12}=31.83A$

$I_s=\sqrt{\frac{2}{3}}{I}_0=\sqrt{\frac{2}{3}}\times 31.83=25.99A$