1. In an induction motor, the ratio of torque exerted at 4% slip to maximum torque, when slip at maximum torque is 12% will be
a) 3/5
b) 5/3
c) 1/3
d) none of these
ans. a
2. In an induction motor the rotor resistance is equal to stand-still reactance then the maximum torque is
a) less than starting torque
b) equal to starting torque
c) more than starting torque
d) none of these
ans. b
3. The complete circle diagram of an induction motor can be drawn with the help of data found from
a) no-load test
b) blocked rotor test
c) a and b
d) a, b and stator resistance test
ans. d
4. The power scale of circle diagram of an induction motor can be found from
a) no-load test only
b) short-circuit test only
c) stator resistance test
d) none of these
ans. b
5. Which of the following is not determined by circle diagram?
a) output
b) efficiency
c) power factor
d) frequency
ans. d
6. The torque of an induction motor in synchronous watt is equal to
a) rotor output
b) stator output
c) stator input
d) watts at rotor speeds
ans. b
7. The shape of torque/slip curve of an induction motor is
a) hyperbola
b) parabola
c) straight line
d) rectangular parabola
ans. d
8. When the frequency of the rotor of an induction motor is small it can be measured by
a) galvanometer
b) dc moving coil millivoltmeter
c) dc moving coil ammeter
d) ac voltmeter
ans. b
9. The stator frame in an induction motor is used
a) as a return path for the flux
b) to hold the armature stamping/stator
c) to protect the whole machine
d) to ventilate the armature
ans. a
10. The speed of a 3-phase cage rotor induction motor depends on
a) frequency of the supply only
b) number of poles only
c) number of poles and frequency of the supply
d) input voltage
ans. c
a) 3/5
b) 5/3
c) 1/3
d) none of these
ans. a
2. In an induction motor the rotor resistance is equal to stand-still reactance then the maximum torque is
a) less than starting torque
b) equal to starting torque
c) more than starting torque
d) none of these
ans. b
3. The complete circle diagram of an induction motor can be drawn with the help of data found from
a) no-load test
b) blocked rotor test
c) a and b
d) a, b and stator resistance test
ans. d
4. The power scale of circle diagram of an induction motor can be found from
a) no-load test only
b) short-circuit test only
c) stator resistance test
d) none of these
ans. b
5. Which of the following is not determined by circle diagram?
a) output
b) efficiency
c) power factor
d) frequency
ans. d
6. The torque of an induction motor in synchronous watt is equal to
a) rotor output
b) stator output
c) stator input
d) watts at rotor speeds
ans. b
7. The shape of torque/slip curve of an induction motor is
a) hyperbola
b) parabola
c) straight line
d) rectangular parabola
ans. d
8. When the frequency of the rotor of an induction motor is small it can be measured by
a) galvanometer
b) dc moving coil millivoltmeter
c) dc moving coil ammeter
d) ac voltmeter
ans. b
9. The stator frame in an induction motor is used
a) as a return path for the flux
b) to hold the armature stamping/stator
c) to protect the whole machine
d) to ventilate the armature
ans. a
10. The speed of a 3-phase cage rotor induction motor depends on
a) frequency of the supply only
b) number of poles only
c) number of poles and frequency of the supply
d) input voltage
ans. c
