Polyphase Induction Motors

A. slip
B. rotor current
C. running torque
D. line voltage

A. e.m.f. injection in rotor eueuit
B. Changing the number of poles
C. Cascade operation
D. None of the above

A. motor takes five to seven times its full load current
B. it will pick-up very high speed and may go out of step
C. it will run in reverse direction
D. starting torque is very high

A. in series
B. in parallel
C. in series-parallel
D. in parallel with stator

A. k/torque with direct switching
B. K x torque with direct switching
C. K2 x torque with direct switching
D. k2/torque with direct switching

A. star connected only
B. delta connected only
C. A. and B. both
D. none of the above

A. low voltage supply
B. high loads
C. harmonics develped in the motor
D. improper design of the machine
E. none of the above

A. By changing the number of stator poles
B. Rotor rheostat control
C. By operating two motors in cascade
D. By injecting e.m.f. in the rotor circuit

A. D.C. compound motor
B. D.C. series motor
C. synchronous motor
D. asynchronous motor

A. zero frequency
B. the same frequency as the slip frequency
C. the same phase as the rotor e.m.f.
D. high value for the satisfactory speed control