A. squirrel-cage induction motors only
B. slip ring induction motors only
C. both A. and (b)
D. none of the above
Related Mcqs:
- If a 3-phase supply is given to the stator and rotor is short circuited rotor will move___________?
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 - 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 - For which motor the speed can be controlled from rotor side ?
A. Squirrel-cage induction motor
B. Slip-ring induction motor
C. Both A. and (b)
D. None of the above - 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 - 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 - In Ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be___________?
A. Ns
B. s.N,
C. (l-s)Ns
D. (Ns-l)s - Size of a high speed motor as compared to low speed motor for the same H.P. will be__________?
A. bigger
B. smaller
C. same
D. any of the above - In squirrel cage induction motors, the rotor slots are usually given slight skew in order to__________?
A. reduce windage losses
B. reduce eddy currents
C. reduce accumulation of dirt and dust
D. reduce magnetic hum - In the squirrel-cage induction motor the rotor slots are usually given slight skew__________?
A. to reduce the magnetic hum and locking tendency of the rotor
B. to increase the tensile strength of the rotor bars
C. to ensure easy fabrication
D. none of the above - The rotor of an induction motor runs at__________?
A. synchronous speed
B. below synchronous speed
C. above synchronous speed
D. any of the above
