Electrical Machine - II (3150910) MCQs

MCQs of Synchronous & Auto Synchronous Motors

Showing 1 to 10 out of 68 Questions
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1.

Which of the following motor is not a doubly excited motor?

(a)

Induction Motor
(b)

DC Motor
(c)

Synchronous Motor
(d)

All of these 
Answer:

Option (a)

2.

Where do we need to use a synchronous motor?

(a)

For constant speed operation 
(b)

For we need to control operating Power Factor 
(c)

Where we have starting arrangement 
(d)

All of these 
Answer:

Option (d)

3.

A synchronous condenser is a synchronous motor work as __________

(a)

No load with under-excited fields
(b)

No-load with over-excited fields
(c)

Normal load with minimum excitation
(d)

Normal load with normal excitation
Answer:

Option (b)

4.

A synchronous condenser is used to _________________________.

 

(a)

improve system power factor
(b)

balance system voltage 
(c)

control self (Synchronous motor) reactive power 
(d)

control active power of load connected in the system  
Answer:

Option (a)

5.

A synchronous phase modifier is a synchronous motor work as __________

(a)

No-load with over-excited fields
(b)

No-load with under-excited fields
(c)

No-load with normal-excited fields
(d)

No-load with Any (Under, Normal & Over)-excited fields
Answer:

Option (d)

6.

A synchronous phase-modifier is used to _________________________.

(a)

improve system power factor
(b)

balance system voltage (transmission line)
(c)

control self (Synchronous motor) reactive power 
(d)

control active power of load connected in the system  
Answer:

Option (b)

7.

What happens if the field winding of the synchronous motor is short-circuited?

(a)

First, starts as induction motor then run as a synchronous motor
(b)

Not start
(c)

Motor will burn out
(d)

Run as an induction motor
Answer:

Option (d)

8.

When the field winding of an unloaded salient pole synchronous motor is open circuited the motor will

(a)

Not start
(b)

Burn
(c)

Run as induction Motor
(d)

Run as variable reluctance motor
Answer:

Option (d)

9.

In a synchronous motor, The normal range of speed regulation is ___________.

(a)

5 to 10 % of No-load Speed 
(b)

5 to 10 % of Full-load Speed 
(c)

Zero %
(d)

Can't say anything without knowing the rotor type (salient pole or cylindrical rotor)
Answer:

Option (c)

10.

The negative phase sequence in a three-phase synchronous motor exists when the motor is

(a)

Supplied with an unbalanced voltage
(b)

Supplied with an unbalanced load
(c)

Unbalanced system fault
(d)

All of the above
Answer:

Option (d)

Showing 1 to 10 out of 68 Questions
1 2 3 4 5 6