Synchronous Generator MCQ Part 3 • Electrical Engineering MCQ

Part 3

Salient pole rotors are generally recommended for which machine construction

Salient pole rotors are generally recommended for which machine:

2 pole
4 pole
6 pole
8 pole

Correct answer: 4. 8 pole

Salient pole alternator construction design for withstanding the stresses at high speeds is difficult to implement, therefore a salient pole alternator turns at low speed. For turning at low speed the pole number needs to be high.

Remember formula: N = 120f/P

Therefore Salient pole rotors are generally recommended for 8 pole machine.

Slip rings are the metal rings that are completely encircling the shaft of a machine but insulated from it

Slip rings are the metal rings that are completely encircling the shaft of a machine but insulated from it:

True
False

Corret answer: 1. True

Which of the following are disadvantages of using brushes in synchronous machines

Which of the following are disadvantages of using brushes in synchronous machines:

They increase the maintenance required
They can cause voltage drop
They cause wear and tear
All of these

Correct answer: 4. All of these

The distortion of the air-gap magnetic field by the current flowing in the stator is technically termed as

The distortion of the air-gap magnetic field by the current flowing in the stator is technically termed as:

Field failure
Eddy loss
Armature reaction
Impulse reaction

Correct answer: 3. Armature reaction

Which of the following parameter of alternator will change if excitation of alternator connected to bus-bar is changed while keeping power input to its mover unchanged

Which of the following parameter of alternator will change if excitation of alternator connected to bus-bar is changed while keeping power input to its mover unchanged:

Power factor
kVA
KVAR
All of these