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Electrical Engineering Objective Questions { Alternators }



15. The main advantage of using fractional pitch winding in an alternator is to reduce
A. amount of copper in the winding
B. size of the machine
C. harmonics in the generated emf
D. cost of the machine

16. In an alternator, if the winding is short pitched by 50 electrical degrees, its pitch factor will be
A.1
B.0.866
C.0.75
D.0.906

17. In alternators, the distribution factor is defined as the ratio of emfs of
A. distributed windings to concentrated winding
B. full pitch winding to distributed winding
C. distributed winding to full pitch winding
D. connectrated winding to distributed winding

18. The maximum current that can be supplied by an alternator depends on
A. speed of the exciter
B. number of poles
C. exciter current
D. strength of the magnetic field

19. The necessary condition for parallel operation of two alternators is
A. terminal voltage should be the same
B. frequency should be the same
C.
D.

20. Two alternators are running in parallel. If the driving force of both the alternators is changed, there will result change in
A. frequency
B. back emf
C. generated voltage
D. all of these

21. In a 3-phase alternator, the unsaturated synchronous reactance of 30 per phase. Then sturated synchronous reactance is
A.30
B. >30
C. <30
D. >>30

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