Question

If a transformer is fed from a 220V and dc supply rather than a 1-phase ac supply, then the transformer will ___________

(a) burn its windings

(b) operate normal

(c) will not operate

(d) will give very small leakage flux

I got this question in exam.

The doubt is from Transformer Phasor Diagram topic in chapter Transformers of Electrical Machines

Answer 1

Correct answer is (a) burn its windings

Easiest explanation: Dc is nothing but ac at zero frequency. So the reactance offered will be zero at dc and the current will be limited only by the small resistance of the winding which will produce very high amount of current to flow through the windings, so burning them up.