64. Insertion of reactance in the rotor circuit
A. reduces starting torque as well as maximum torque
B.increases starting torque as well as maximum torque motor if air-gap is magnetizing generate (c) increases starting torque but maximum torque .emains unchanged
C.(d) increases starting torque but maximum torque decreases
D.
65. 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 reamins same
66. For driving high inertia loads best type of induction motor suggested is
A. slip ring type
B. squirrel cage type
C. any of the above
D. none of the above
67. 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
68. The purpose of using short-circuit gear is
A. to short circuit the rotor at slip rings
B. to short circuit the starting resistances in the starter
C. to short circuit the stator phase of motor to form star
D. none of the above
69. In a squirrel cage motor the induced e.m.f. is
A. depended on the shaft loading
B. dependent on the number of slots
C. slip times the stand still e.m.f. induced in the rotor
D. none of the above
70. Less maintenance trouble are experienced in case of
A. slip ring induction motor
B. squirrel cage induction motor
C. both (a) and (b)
D. none of the above
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