Question

A step-down delta-star transformer, with per-phase turns ration of 5, is fed from a 3-phase, 1100 V, 50 Hz source. The secondary of this transformer through a 3-pulse type rectifier feeds a R load of 10 Ω. Find the maximum value of the load current (phase).

(a) √2 x 22 A

(b) 1 x 11 A

(c) √2 x 11 A

(d) 1 x 22 A

This question was posed to me by my college professor while I was bunking the class.

I need to ask this question from 3P-Diode Rectifiers-1 topic in chapter Diode Rectifiers of Power Electronics

Answer 1

The correct answer is (a) √2 x 22 A

To explain: Vph = 1100/5 = 220 V (Transformer ratio = 5)

Vmp = √2 x 220 V

Imp = Vmp/R.