Question

At the instant of starting, when a DC motor is put on supply, it will behave like ______________

(a) Highly resistive circuit

(b) Low resistance circuit

(c) Capacitive circuit

(d) Inductive circuit

I have been asked this question at a job interview.

I want to ask this question from DC Motor Basics -2 in chapter DC Motors of DC Machines

Answer 1

Correct answer is (b) Low resistance circuit

For explanation: At the starting when back emf is very low, machine will fetch large amount of armature current from supply acting as a low resistive circuit. In order to avoid such case, we use starters in DC machine which add some resistance to armature at the starting.