1. Which of the following generating station has the minimum running cost?

Hydro-electric

Nuclear power

Thermal power

Diesel

2. An electric motor in which rotor and stator field rotate simultaneously is called a_ motor

Dc

Induction

Synchronous

Universal

3. In an efficient transformer, the energy transferred from input to output

Is 100%

Is above 90%

Depend on turn ratio

Depend on core area

4. Power failure relays operate in most stand by power installations when the normal phase voltage falls to _ percent

95

80

70

50

5. Three phase alternator are invariably Y - connected because

Magnetic losses are the minimum

Less turns of wire are required

Smaller conductors can be used

Higher terminal voltage is obtained

6. The power factor of an alternator is determined by it’s

Speed

Load

Excitation

Prime mover

7. Unlike dc generator kw rating alternators are rated in

Kva

Kvar

Kwh

Mw

8. The pitch factor for 3rd harmonic in an alternator having 18 slots/ pole and coil span 5/6 of pole pitch is

0.707

0.259

0.966

1

9. Dampers in a large generator

Increase stability

Reduce voltage fluctuations

Reduce frequency fluctuations

None of above

10. A synchronous generator gives out put at the standard frequency. This frequency can be increase by

Increasing the field current

Increasing the speed of the armature

Increasing the speed of the field

Decreasing the field current