Question

The great advantage of the double squirrel-cage induction motor over single cage rotor is that its _________

(a) efficiency is higher

(b) power factor is higher

(c) slip is larger

(d) starting current is lower

The question was asked in an interview for internship.

I'm obligated to ask this question of Induction Motor as a Transformer topic in section Induction Machines of Electrical Machines

Answer 1

Right option is (d) starting current is lower

For explanation I would say: The outer cage has higher resistance and low reactance while vice versa for the inner cage. So at starting the current is confined to outer cage with the reduction in starting current improving the torque.