Question

A single-phase half-wave rectifier with a FD is supplied by Vs = 240 V, 50 Hz, AC source with a load R = 10 Ω, L = 0.8 mH. The firing angle is so adjusted such that the output voltage obtained is 100 V. Find the firing angle.

(a) 62°

(b) 102°

(c) 31°

(d) 47°

The question was posed to me in a job interview.

Query is from Single-Phase HW AC-DC-4 in portion Converters of Power Electronics

Answer 1

Correct choice is (c) 31°

The best I can explain: Vo = Vm/2π cos(firing angle).