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

The stating torque of the slip ring induction motor can be increased by adding__________?

A. External inductance to the rotor
B. External resistance to the rotor
C. External capacitance to the rotor
D. Both resistance and inductance to rotor

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

The power scale of circle diagram of an induction motor can be found from__________?

A. Stator resistance test
B. No-load test only
C. Short-circuit test only
D. Noue of the above

A change of 4% of supply voltage to an induction motor will produce a change of approximately ________?

A. 4% in the rotor torque
B. 8% in the rotor torque
C. 12% in the rotor torque
D. 16% in the rotor torque

The shape of the torque/slip curve of induction motor is__________?

A. Parabola
B. Hyperbola
C. Rectangular parabola
D. Straigth line

The vafcie of transformation ratio of an induction motor can be found by__________?

A. Open-circuit test only
B. Short-circuit test only
C. Stator resistance test
D. None of the above

In a three-phase induction motor__________?

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 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

Which is of the following data is required to draw the circle diagram for an induction motor ?

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