The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is

The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excit

1.	The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is
A.	30 Hz
B.	70 Hz
C.	20 Hz
D.	35 Hz
Answer» C. 20 Hz