Q. 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