Electrical Machine - II (3150910) MCQs

MCQs of Synchronous & Auto Synchronous Motors

Showing 61 to 68 out of 68 Questions
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61.

Stability of a synchronous machine

(a)

Decreases with increase in its excitation
(b)

Remains unaffected with an increase in excitation
(c)

Increases with increase in its excitation
(d)

All of these 
Answer:

Option (c)

62.

Which of the following motors will be used in electric clocks

(a)

D.C. shunt motor
(b)

D.C. series motor
(c)

A.C. induction motor
(d)

A.C. synchronous motor
Answer:

Option (d)

63.

The efficiency of a properly designed synchronous motor will usually fall in range

(a)

60 to 70%
(b)

75 to 80%
(c)

85 to 95%
(d)

99 to 99.5%
Answer:

Option (c)

64.

The net armature voltage (Er) of a synchronous motor is equal to the

(a)

Vector sum of Eb and V
(b)

Arithmetic sum of Eb and V
(c)

Vector difference between Eb and V
(d)

Arithmetic difference between Eb and V
Answer:

Option (c)

65.

In a synchronous motor damper windings are provided on

(a)

Stator frame
(b)

Rotor shaft
(c)

Poles faces
(d)

None of the above
Answer:

Option (c)

66.

The torque is being developed When the stator pulls the rotor into synchronism is know as 

(a)

Starting torque
(b)

Pull-out torque
(c)

Pull-in torque
(d)

Running torque
Answer:

Option (c)

67.

The coupling angle or load angle of a synchronous motor is defined as the angle between the

(a)

Rotor and stator teeth
(b)

Rotor and the stator poles of opposite polarity
(c)

Rotor and the stator poles of the same polarity
(d)

All of these
Answer:

Option (b)

68.

A pony motor is basically

(a)

Small induction motor
(b)

D.C series motor
(c)

D.C shunt motor
(d)

Double winding A.C/D.C motor
Answer:

Option (a)

Showing 61 to 68 out of 68 Questions
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