Question

A 3-phase slip ring IM is has its copper bars replaced by the aluminium bars in the machine. With the above change ___________

(a) starting torque increases, maximum torque remains same, smT increase

(b) starting torque increases, maximum torque remains same, smT remains same

(c) starting torque increases, maximum torque remains increases, smT increase

(d) starting torque decreases, maximum torque remains same, smT decrease

I have been asked this question in semester exam.

My question is based upon Starting of Polyphase Induction Motors-II topic in portion Starting of Induction Motors of Electrical Machines

Answer 1

Correct choice is (a) starting torque increases, maximum torque remains same, smT increase

The explanation is: As the resistance has been changed as the aluminium has replaced copper, it will not affect the maximum torque.