1. An alternator is also called
(a) synchronous generator.
(b) turbo generator.
(c) asynchronous generator.
(d) generator.
Answer ⇓
2. Alternators are rated in
(a) kW.
(b) kVAR.
(c) kVA.
(d) HP.
Answer ⇓
3. Three phase alternators are generally
(a) star connected.
(b) delta connected.
(c) open circuited.
(d) short circuited.
Answer ⇓
4. In large alternators damper winding is used to improve
(a) speed.
(b) efficiency.
(c) stability.
(d) power factor.
Answer ⇓
5. In synchronous generator, the purpose of using damper winding is to
(a) reduce the hunting effect.
(b) reduce the armature reaction effect.
(c) provide starting torque.
(d) all of the above.
Answer ⇓
6. In alternators fractional pitch coil are used to reduce the effect of
(a) hunting.
(b) harmonics.
(c) armature reaction.
(d) power factor.
Answer ⇓
7. If the driving force of two alternators operating in parallel is changed, this result change in
(a) generated voltage.
(b) frequency.
(c) back emf.
(d) reactive power.
Answer ⇓
8. If the excitation of two alternators operating in parallel is changed, this result change in
(a) generated voltage.
(b) frequency.
(c) back emf.
(d) reactive power.
Answer ⇓
9. Two alternator operating in parallel must have same
(a) voltage.
(b) frequency.
(c) phase sequence.
(d) all of the above.
Answer ⇓
10. The power factor of an alternator is controlled by its
(a) speed.
(b) load.
(c) excitation.
(d) prime mover.
Answer ⇓
11. Active power of an alternator can be varied by
(a) changing field excitation.
(b) changing of prime cover speed.
(c) changing the load.
(d) none of the above.
Answer ⇓
12. In an alternator, potier triangle is used to determine
(a) power factor.
(b) synchronous impedance.
(c) rotor current.
(d) voltage regulation.
Answer ⇓
13. The full load terminal voltage of an alternator is greater than no load terminal voltage when
(a) load is highly inducted.
(b) load is highly capacitive.
(c) alternator is under excitation.
(d) input mechanical power is increased.
Answer ⇓
14. Under short-circuit conditions, the power factor of an alternator is
(a) unity.
(b) almost zero lagging.
(c) almost zero leading.
(d) same as normal condition.
Answer ⇓
15. Synchronous generator will develope maximum power when
(a) power angle is equal to internal angle.
(b) connected load is fully resistive.
(c) over excitated.
(d) no load is connected.