Question

A 10 KVA, 2000/200 V, single phase transformer operating at 50 Hz with a current of 50 A flowing through the l.v. winding. Then the Self inductance of l.v. winding is?

(a) 12.7mH

(b) 1.27 mH

(c) 12.7H

(d) 0.127 H

I got this question in unit test.

This intriguing question comes from Transformer as a Magnetically Coupled Circuit topic in division Transformers of Electrical Machines

Answer 1

Correct option is (a) 12.7mH

Easiest explanation: Flux linkages on l.v. = N*φ = E/(4.44*f)

                           = 200/(4.44*50)   = 0.9 AT

               Self inductance = mutual flux linkage/peak current

                             = 0.9/(1.414*50)

                             = 0.0127 H.