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Free download in PDF Single Phase Induction Motor Short Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
41
A reluctance motor
[A]
is self-starting
[B]
is constant speed motor
[C]
needs no D.C. excitation
[D]
all of the above
42
As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for
[A]
fans
[B]
blowers
[C]
sound equipment
[D]
mixer grinders
43
Which motor is normally free from mechanical and magnetic vibrations ?
[A]
Split phase motor
[B]
Universal motor
[C]
Hysteresis motor
[D]
Shaded pole motor
44
In which single-phase motor, the rotor has no teeth or winding ?
[A]
Split phase motor
[B]
Reluctance motor
[C]
Hysteresis motor
[D]
Universal motor
45
The direction of rotation of universal motor can be reversed the by reversing the flow of current through
[A]
armature winding
[B]
field winding
[C]
either armature winding or field winding
[D]
none of the above
Answer: either armature winding or field winding
46
When a D.C. series motor is connected to A.C. supply, the power factor will be low because of
[A]
high inductance of field and armature circuits
[B]
induced current in rotor due to variations of flux
[C]
fine copper wire winding
[D]
none of the above
Answer: high inductance of field and armature circuits
47
Which of the following motors can be used for unity power factor ?
[A]
Capacitor run motor
[B]
Shaded pole motor
[C]
Hysteresis motor
[D]
Schrage motor
48
The speed of a universal motor is generally reduced by using
[A]
gear trains
[B]
V-belts
[C]
brakes
[D]
chains
49
Which type of load is offered by cranes and hoists ?
[A]
Gradually varying load
[B]
Non-reversing, no-load start
[C]
Reversing, light start
[D]
Reversing, heavy start
Answer: Reversing, heavy start
50
Which of the following single-phase motors has relatively poor starting torque ?
[A]
Universal motor
[B]
Repulsion motor
[C]
Capacitor motor
[D]
All single phase motors have zero starting torque
51
The wattage of motor for driving domestic sewing machine will be around
[A]
100 to 150 W
[B]
40 to 75 W
[C]
10 to 30 W
[D]
5 to 10 W
52
The wattage rating for a ceiling fan motor will be in the range
[A]
200 to 250 W
[B]
250 to 500 W
[C]
50 to 150 W
[D]
10 to 20 W
53
In case of high speed universal motor which of the following needs more attention ?
[A]
End play
[B]
Air gap
[C]
Insulation in rotor
[D]
Balancing of rotor
Answer: Balancing of rotor
54
In case of a shaded pole motor the direction of rotation of the motor is
[A]
from main pole to shaded pole
[B]
from shaded pole to main pole
[C]
either of the above depending on voltage
[D]
either of the above depending on power factor
Answer: from main pole to shaded pole
55
The repulsion-start induction-run motor is used because of
[A]
good power factor
[B]
high efficiency
[C]
minimum cost
[D]
high starting torque
Answer: high starting torque
56
Which of the following motors has highest starting torque ?
[A]
Repulsion motor
[B]
Shaped pole motor
[C]
Capacitor-start motor
[D]
Split-phase motor
Answer: Capacitor-start motor
57
Which of the following single-phase induction motors is generally used in time phonographs ?
[A]
Resistance start
[B]
Capacitor start capacitor run
[C]
Shaded pole
[D]
Universal
58
In A.C. series motor compensating winding is employed to
[A]
reduce the effects of armature reaction
[B]
increase the torque
[C]
reduce sparking at the brushes
[D]
none of the above
Answer: reduce sparking at the brushes
59
Which of the following motors can be run on AC. as well as D.C. supply ?
[A]
Universal motor
[B]
Repulsion motor
[C]
Synchronous motor
[D]
Reluctance motor
60
In a hysteresis motor, the rotor must have
[A]
retentivity
[B]
resistivity
[C]
susceptibility
[D]
none of the above
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