Question

In the circuit shown below,



If the firing angle $\alpha$ is zero degree, then the circuit turn off time of each thyristor is ________ms.

• A. 13.33

Answer 1

The correct option is A 13.33
In a three phase fully controlled converter each thyristor conductors for ${120}^{\circ }$ if $\alpha =0^{\circ }$ and will be in reverse bias for ${240}^{\circ }$
$\omega t_c={240}^{\circ }$
$t_c=\frac{{240}^{\circ }}{2\pi \times 50}\times \frac{\pi }{{180}^{\circ }}$
$t_c=$ circuit turn off time$=13.33ms$.