1. If a motor of lower speed is purchased in place of high speed motor, its cost will be
a) same
b) more
c) less
d) slightly less
ans. b
2. If a 3-phase induction motor runs at 25% supply than the rated voltage , the motor will
a) not start
b) start at lower speed
c) run at normal speed
d) get heated and damaged
ans. d
3. If a 3-phase induction motor runs on 2-phase supply it will
a) run at slow speed
b) run with jerks
c) likely to burn
d) blow off the fuses
ans. c
4. The speed of the squirrel cage induction motor can be controlled by
a) changing supply frequency
b) changing number of poles
c) reducing supply voltage
d) all of these
ans. d
5. The speed of the slip ring induction motor can be controlled by
a) changing supply frequency
b) changing number of poles
c) changing the resistance of the rotor winding
d) all of these
ans. d
6. The speed of the squirrel cage induction motor can be controlled from
a) stator side
b) rotor side
c) stator and rotor sides both
d) supply voltage side
ans. a
7. The speed of an induction motor is
a) always less than the synchronous speed
b) can be equal to or less than the synchronous speed
c) always more than the synchronous speed
d) none of these
ans. a
8. The speed of the rotor field of an induction motor
a) is equal to synchronous speed
b) is equal to motor speed
c) is equal to zero
d) none of these
ans. a
9. Majority of the induction motors have
a) totally enclosed frame
b) drip proof type frame
c) totally enclosed fan closed frame
d) none of these
ans. c
10. The squirrel cage rotor at at 4-pole induction motor
a) can be used for only 4 pole induction motor
b) can be used for motors having 2,4 or 8 poles only
c) can be used for motor with any number of poles
d) none of these
ans. c
a) same
b) more
c) less
d) slightly less
ans. b
2. If a 3-phase induction motor runs at 25% supply than the rated voltage , the motor will
a) not start
b) start at lower speed
c) run at normal speed
d) get heated and damaged
ans. d
3. If a 3-phase induction motor runs on 2-phase supply it will
a) run at slow speed
b) run with jerks
c) likely to burn
d) blow off the fuses
ans. c
4. The speed of the squirrel cage induction motor can be controlled by
a) changing supply frequency
b) changing number of poles
c) reducing supply voltage
d) all of these
ans. d
5. The speed of the slip ring induction motor can be controlled by
a) changing supply frequency
b) changing number of poles
c) changing the resistance of the rotor winding
d) all of these
ans. d
6. The speed of the squirrel cage induction motor can be controlled from
a) stator side
b) rotor side
c) stator and rotor sides both
d) supply voltage side
ans. a
7. The speed of an induction motor is
a) always less than the synchronous speed
b) can be equal to or less than the synchronous speed
c) always more than the synchronous speed
d) none of these
ans. a
8. The speed of the rotor field of an induction motor
a) is equal to synchronous speed
b) is equal to motor speed
c) is equal to zero
d) none of these
ans. a
9. Majority of the induction motors have
a) totally enclosed frame
b) drip proof type frame
c) totally enclosed fan closed frame
d) none of these
ans. c
10. The squirrel cage rotor at at 4-pole induction motor
a) can be used for only 4 pole induction motor
b) can be used for motors having 2,4 or 8 poles only
c) can be used for motor with any number of poles
d) none of these
ans. c
