# Objective Questions on Alternators | Part 3

- Link: https://studyelectrical.com/2014/01/objective-questions-on-alternators-3.html
- Published: 2014-01-18T09:17:00+00:00

[Part 1](http://www.studyelectrical.com/2014/12/objective-questions-mcq-on-alternator-1.html)
[Part 2](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-2.html)
[Part 3](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-3.html)
[Part 4](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-4.html)
[Part 5](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-5.html)

31. In order to reduce the harmonics in the emf generated in an alternator
(A) slots
are skewed(B) salient pole tips are chamfered(C) winding is well distributed(D) 
all of the above.

32. The maximum power in a synchronous machine is obtained when the load angle is

(A) 0°(B) 85°(C) 120°(D) 135°.

33. The emf generated due to nth harmonic component of flux in an alternator will
be
(A) n times the fundamental emf(B) same as fundamental emf(C) less than the value
of fundamental emf.

34. Synchronizing torque comes into operation under all of the following cases 
EXCEPT(A) phase difference between two voltages(B) frequency difference between 
two voltages(C) voltage difference between two voltages(D) reduction in exciting
current in one of the alternators.

35. Unbalanced 3-phase stator currents cause(A) double frequency currents in the
rotor(B) healing of rotor(C) vibrations(D) all of the above.

36. In large generators protection provided against external faults is(A) biased
differential protection(B) sensitive earth fault protection(C) inter-turn fault 
protection(D) all of the above.

37. Pitch factor is the ratio of the emfs of(A) short pitch coil to full pitch 
coil(B) full pitch winding to concentrated winding(C) full pitch winding to short
pitch winding(D) distributed winding to full pitch winding.

38. In an alternator if the winding is short pitched by 50 electrical degrees, 
its pitch factor will be(A) 1.0(B) 0.866(C) 0.75(D) 0.50.

39. The Potier’s triangle separates(A) stator losses and rotor losses(B) fixed 
losses and variable losses(C) armature voltage and field voltage(D) armature leakage
reactance and armature reaction mmf.

40. If a single phase alternator has 8 slots per pole uniformly speed, but the 
winding is arranged with the middle two left empty, the breadth coefficient will
be(A) 0.99(B) 0.88(C) 0.67(D) 0.53.

41. Two alternators are running in parallel. If the field of one of the alternator
is adjusted, it will(A) reduce its speed(B) change its load(C) change its power 
factor(D) change its frequency.

42. A generator is operating by itself supplying the system loads. The reactive
power supplied by the generator will(A) depend on prime mover rpm(B) depend on type
of insulation used(C) depend on the amount demanded by the load(D) depend on inter-
coil inductance.

43. Which of the following part plays important role in over speed protection of
a generator ?(A) Over current relay(B) Alarm(C) Differential protection(D) Governor.

[⌊Sample Job Interview Questions⌉⌊Sample Job Interview Questions⌉[44. Which type
of protection is provided on a generator to protect against stator insulation failure?(
A) Differential protection(B) Thermocouple actuated alarm(C) Over current relay(
D) Reverse power relay.

45. Which relays comes into operation in the event of the failure of prime mover
connected to ihe generator ?
(A) Reverse power relay(B) Differential relay(C) Buchholz
relay(D) None of the above.

[Part 1](http://www.studyelectrical.com/2014/12/objective-questions-mcq-on-alternator-1.html)
[Part 2](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-2.html)
[Part 3](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-3.html)
[Part 4](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-4.html)
[Part 5](http://www.studyelectrical.com/2014/12/objective-questions-on-alternators-5.html)

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