Alternator Multiple Choice Questions and Answers

31. For a machine on infinite bus active power can be varied by

   A.Changing field excitation

   B.Changing of prime cover speed

   C.Both (a) and (b) above

   D.None of the above

32. Squirrel-cage bars placed in the rotor pole faces of an alternator help reduce hunting

   A.Above synchronous speed only

   B.Below synchronous speed only

   C.Above and below synchronous speed both

   D.None of the above

33. The load sharing between two steam-driven alternators operating in parallel may be adjusted by varying the

   A.Field strengths of the alternators

   B.Power factors of the alternators

   C.Steam supply to their prime movers

   D.Speed of the alternators

34. Keeping its excitation constant, if steam supply of an alternator running in parallel with another identical alternator is increased, then

   A.It would over-run the other alternator

   B.Its rotor will fall back in phase with respect to the other machine

   C.It will supply greater portion of the load

   D.Its power factor would be decreased

35. Two identical alternators are running in parallel and carry equal loads. If excitation of one alternator is increased without changing its steam supply, then

   A.It will keep supplying almost the same load

   B.kVAR supplied by it would decrease

   C.Its p.f. will increase

   D.kVA supplied by it would decrease

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