A. in the opposite direction as the direction of the rotating field
B. in the same direction as the direction of the field
C. in any direction depending upon phase squence of supply
Related Mcqs:
- When /?2 is the rotor resistance, .X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running conditions will be_____________?
A. sR2X2 = 1
B. sR2 = X2
C. R2 = sX2
D. R2 = s2X2 - If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as____________?
A. humming
B. hunting
C. crawling
D. cogging - In an induction motor the relationship between stator slots and rotor slots is that_____________?
A. stator slots are equal to rotor slots
B. stator slots are exact multiple of rotor slots
C. stator slots are not exact multiple of rotor slots
D. none of the above - What will happen if the relative speed between the rotating flux of stator and rotor of the induction motor is zero ?
A. The slip of the motor will be 5%
B. The rotor will not run
C. The rotor will run at very high speed
D. The torque produced will be very large - A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?
A. will continue running burning its one phase
B. will continue running burning its two phases
C. will stop and carry heavy current causing permanent damage to its winding
D. will continue running without any harm to the winding - Temperature of the stator winding of a three phase induction motor is obtained by___________?
A. resistance rise method
B. thermometer method
C. embedded temperature method
D. all above methods - A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?
A. 200 Hz
B. 50 Hz
C. 2 Hz
D. 0.2 Hz - In a three-phase induction motor, the number of poles in the rotor winding is always__________?
A. zero
B. more than the number of poles in stator
C. less than number of poles in stator
D. equal to number of poles in stator - In three-phase induction motors sometimes copper bars are placed deep in the rotor to___________?
A. improve starting torque
B. reduce copper losses
C. improve efficiency
D. improve power factor - Insertion of resistance in the rotor of an induction motor to develop a given torque?
A. decreases the rotor current
B. increases the rotor current
C. rotor current becomes zero
D. rotor current rernains same
