Electrical Machine - II (3150910) MCQs

MCQs of Single-Phase Induction Motors

Showing 21 to 30 out of 50 Questions
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21.

When the rotor reached ___________ (rated speed), the centrifugal switch (CS) connected in series with starting winding will disconnect the ___________ from 1-Φ supply.

 

(a)

20-30 % speed,     auxiliary winding
(b)

40-50 % speed,     main winding
(c)

70-80 % speed,     auxiliary winding
(d)

50 % speed,      main winding
Answer:

Option (c)

22.

The angle between the main winding and auxiliary winding is around ____________ in Resistance split-phase motor.

(a)

10-20 degrees
(b)

30-40 degrees
(c)

70-90 degrees
(d)

90 degrees
Answer:

Option (b)

23.

The angle between the main winding and auxiliary winding is around ____________ in Capacitor split-phase motor.

(a)

10-20 degrees
(b)

30-40 degrees
(c)

70-90 degrees
(d)

20 degrees
Answer:

Option (c)

24.

In a two-value capacitor motor, the capacitor used for running purposes is ________________ & _______________ duty.

(a)

Electrolytic Capacitor,     Intermediate duty 
(b)

Ceramic type,     Intermediate duty 
(c)

Air capacitor,     continuous
(d)

Paper spaced oil-filled type,     continuous
Answer:

Option (d)

25.

In shaded pole motor, the direction of rotation of motor is

(a)

From shaded pole to unshaded pole
(b)

From the unshaded to shaded pole
(c)

Either 1 or 2
(d)

How supply terminal connected with the stator winding
Answer:

Option (b)

26.

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 or Field
(d)

both of the winding
Answer:

Option (c)

27.

In repulsion motor, maximum torque is developed when

(a)

Brush axis is at 90° electrical to the field axis
(b)

Brush axis is at 0° electrical to the field axis
(c)

Brush axis is at 45° electrical to the field axis
(d)

Brush axis is at 10° electrical to the field axis
Answer:

Option (c)

28.

If the centrifugal switch does not open at 70 to 80 % of the rated speed of a motor, then it can _______________

(a)

Damage to the runing winding
(b)

Damage to the starting winding
(c)

Damage to the centrifugal switch
(d)

Overloading of running winding
Answer:

Option (b)

29.

Speed torque characteristic of a repulsion induction motor is similar to that of 

(a)

DC Series Motor
(b)

Capacitor start induction motor
(c)

shaded pole motor 
(d)

Universal Motor
Answer:

Option (a)

30.

The rotor slots skewed to _________ degree in a Shaded Pole motor to ______________

(a)

20,          Improve power factor
(b)

45,         Improve efficiency
(c)

60,        obtain an optimum starting torque and for limiting the torque dip during the run-up
(d)

0,        Reducing the locking tendency
Answer:

Option (c)

Showing 21 to 30 out of 50 Questions
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