Which of the following component is usually fabricated out of silicon steel ?
A. Bearings
B. Shaft
C. Statorcore
D. None of the above
Polyphase Induction Motors
An induction motor with 1000 r.p.m. speed will have____________?
An induction motor with 1000 r.p.m. speed will have____________?
A. 8 poles
B. 6 poles
C. 4 poles
D. 2 poles
The term ‘cogging’ is associated with___________?
The term ‘cogging’ is associated with___________?
A. three phase transformers
B. compound generators
C. D.C. series motors
D. induction motors
The number of slip rings on a squirrel cage induction motor is usually____________?
The number of slip rings on a squirrel cage induction motor is usually____________?
A. two
B. three
C. four
D. none
The efficiency of an induction motor can be expected to be nearly____________?
The efficiency of an induction motor can be expected to be nearly____________?
A. 60 to 90%
B. 80 to 90%
C. 95 to 98%
D. 99%
A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?
A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?
A. 200 Hz
B. 50 Hz
C. 2 Hz
D. 0.2 Hz
In case the air gap in an induction motor is increased?
In case the air gap in an induction motor is increased?
A. the magnetising current of the rotor will decrease
B. the power factor will decrease
C. speed of motor will increase
D. the windage losses will increase
In an induction motor, no-load the slip is generally____________?
In an induction motor, no-load the slip is generally____________?
A. less than 1%
B. 1.5%
C. 2%
D. 4%
The shaft of an induction motor is made of_____________?
The shaft of an induction motor is made of_____________?
A. high speed steel
B. stainless steel
C. carbon steel
D. cast iron
The torque of an induction motor is___________?
The torque of an induction motor is___________?
A. directly proportional to slip
B. inversely proportional to slip
C. proportional to the square of the slip
D. none of the above