Question

In a $3-\varphi$ full converter thyristor bridge, if source consists of 2 mH inductor on each phase and fed from 415 V rms (L - L) at 50 Hz, then the voltage regulation due to source inductance is _______ %

(Assume constant load current of 20 A and firing angle is ${30}^{\circ }$)

• A. 2.47

Answer 1

The correct option is A 2.47
In a $3-\varphi$ full converter, voltage regulation due to source inductance is

$V.R=\frac{3\omega L_3{I}_0}{\pi }\times \frac{1}{V_0\left(atnoload\right)}=\frac{3\times 2\pi f{L}_s{I}_0\pi }{\pi 3V_{mL}cos\alpha }$

$V.R=\frac{2\pi f{L}_s{I}_o}{V_{mL}cos\alpha }=\frac{2\pi \times 50\times 2\times {10}^{-3}\times 20}{\sqrt{2}\times 415\times cos\left({30}^{\circ }\right)}$

% V.R = 2.47%