A 500 kW, 3-phase, 440 volts, 50 Hz, A.C. induction motor has a speed of 960 r.p.m. on full load. The machine has 6 poles. The slip of the machine will be__________?
A. 0.01
B. 0.02
C. 0.03
D. 0.04
A. 0.01
B. 0.02
C. 0.03
D. 0.04
A. stator resistance test
B. no-load test only
C. short-circuit test only
D. noue of the above
The power scale of circle diagram of an induction motor can be found from__________? Read More »
Polyphase Induction Motors A. 4% in the rotor torque
B. 8% in the rotor torque
C. 12% in the rotor torque
D. 16% in the rotor torque
A. parabola
B. hyperbola
C. rectangular parabola
D. straigth line
The shape of the torque/slip curve of induction motor is__________? Read More »
Polyphase Induction Motors A. open-circuit test only
B. short-circuit test only
C. stator resistance test
D. none of the above
The vafcie of transformation ratio of an induction motor can be found by__________? Read More »
Polyphase Induction Motors A. power factor at starting is high as compared to that while running
B. power factor at starting is low as compared to that while running
C. power factor at starting in the same as that while running
In a three-phase induction motor__________? Read More »
Polyphase Induction Motors A. improve starting torque
B. reduce copper losses
C. improve efficiency
D. improve power factor
A. Block rotor test only
B. No load test only
C. Block rotor test and no-load test
D. Block rotor test, no-load test and stator resistance test
A. pulling the motor directly on line without a starter
B. locking of rotor due to harmonics
C. starting the motor on load which is more than the rated load
D. interchanging two supply phases for quick stopg
In case of 3-phase induction motors, plugging means__________? Read More »
Polyphase Induction Motors A. iron losses in stator will be negligible as compared to that in rotor
B. iron losses in motor will be neg¬ligible as compared to that in rotor
C. iron losses in stator will be less than that in rotor
D. iron losses in stator will be more than that in rotor
In a three-phase induction motor_______________? Read More »
Polyphase Induction Motors