Question

A 3-phase induction motor taking a line current of 200 A, is started by direct switching. If an auto transformer of with 50% tapping is made to be used, the motor line current and supply line current will be respectively?

(a) 100, 50

(b) 50, 100

(c) 50, 200

(d) 50*1.73, 200

I have been asked this question in an interview for job.

My doubt stems from Applications of Polyphase Induction Motors in section Induction Machines of Electrical Machines

Answer 1

Correct answer is (a) 100, 50

Explanation: The motor line current will reduce by a fold of four times and the line current by half.