Question

There is a 10 KVA, 2000/200 V, single phase transformer having below following parameters are r1=10Ω, r2=0.1Ω, l1 = 40mH, l2=0.4 mH, M = 10H. Then the expected secondary self inductance will be?

(a) 100.04H

(b) 99.06H

(c) 1.0004H

(d) 10.04H

I got this question in an interview for internship.

My question is taken from Transformer as a Magnetically Coupled Circuit topic in section Transformers of Electrical Machines

Answer 1

Correct answer is (c) 1.0004H

The best I can explain: Secondary self inductance = L2 = Lm2 + l2

                                     = (N2/N1)*M + l2

         = 200/2000*10 + 0.0004H

                    = 0.0004 H.