Question

The rotor of 3-phase slip ring induction motor is fed from a 3-phase supply with its stator winding short circuited having rotor rotating clockwise at a speed of Nr, then the _________

(a) speed of air gap field w.r.t. stator is Ns-Nr anticlockwise

(b) speed of air gap field w.r.t. stator is Ns-Nr clockwise

(c) speed of airgap field w.r.t rotor is Ns clockwise

(d) speed of airgap field w.r.t. stator is Ns-Nr clockwise

I have been asked this question in final exam.

I want to ask this question from Induction Motor as a Transformer topic in section Induction Machines of Electrical Machines

Answer 1

Correct option is (a) speed of air gap field w.r.t. stator is Ns-Nr anticlockwise

Explanation: The air gap field of stator = -(Ns-Nr).