Question 1

An important advantage of a synchronous motor over wound round induction motor is that

Accepted Answer

A) its power factor may be varied at will 
B) its speed is independent of supply frequency 
C) its speed may be controlled more easily 
D) none of the above 
A) its power factor may be varied at will 
B) its speed is independent of supply frequency 
C) its speed may be controlled more easily 
D) none of the above

Question 2

If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor

Accepted Answer

A) become more 
B) become less 
C) remain constant 
D) none of the above 
A) become more 
B) become less 
C) remain constant 
D) none of the above

Question 3

The armature current of the synchronous motor has higher values for

Accepted Answer

A) high excitation only 
B) low excitation only 
C) both (a) and (b) 
D) none of the above 
A) high excitation only 
B) low excitation only 
C) both (a) and (b) 
D) none of the above

Question 4

If one-phase of a 3-phase synchronous motor is short-circuited, motor

Accepted Answer

A) will refuse to start 
B) will overheat in spots 
C) will not come upto speed 
D) will fail to pull into step 
A) will refuse to start 
B) will overheat in spots 
C) will not come upto speed 
D) will fail to pull into step

Question 5

Stability of a synchronous machine

Accepted Answer

A) decreases with increase in its excitation 
B) increases with increase in its excitation 
C) remains unaffected with increase in excitation 
D) any of the above 
A) decreases with increase in its excitation 
B) increases with increase in its excitation 
C) remains unaffected with increase in excitation 
D) any of the above

An important advantage of a synchronous motor over wound round induction motor is that

If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor

The armature current of the synchronous motor has higher values for

If one-phase of a 3-phase synchronous motor is short-circuited, motor

Stability of a synchronous machine

Synchronous Motors: Part A

Synchronous Motor: Part B

Synchronous Motor Characteristics and Applications

Synchronous Motor: Power Factor, Back EMF, Torque, Losses

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Exam 3: Synchronous Motors and Their Operation

An important advantage of a synchronous motor over wound round induction motor is that

If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor

The armature current of the synchronous motor has higher values for

If one-phase of a 3-phase synchronous motor is short-circuited, motor

Stability of a synchronous machine

Synchronous Motors: Part A

Synchronous Motor: Part B

Synchronous Motor Characteristics and Applications

Synchronous Motor: Power Factor, Back EMF, Torque, Losses

Filters