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MCQ – Alternators
#1. Alternators are rated in....?
#2. What is the number of poles if the speed is 3000 rpm and frequency is 50Hz of an alternator?
N = 120f/P
P= (120 x 50)/3000 = 2
#3. Alternator oerates on the principle of....?
#4. Salient pole alternators used at.....?
#5. Alternator is also called.....?
#6. A 4 pole 1500 rpm alternator will generate emf at the frequency of......?
N = 120f/p
f = (1500 x 4) /120= 50
#7. The Stator core is laminated, this is to reduce....?
#8. In modern alternators, the rotating part is....?
#9. In synchronous machine stator frame is made up of...?
#10. In synchronous machine stator core is made up of...?
#11. Which type of alternator used in hydroelectric power station?
#12. In high speed application which type alternator is used?
#13. Which type of alternator used in Steam power station?
#14. A 6 pole 60 Hz alternator runs at speed of ..... rpm?
(120 x 60) / 6 =1200
#15. Field system of alternator is excited at use of...?
#16. In case of turbo alternators, rotor made of...?
#17. In salient pole structure the pole shoes covers about...?
#18. A large diameter and short axial length alternator running at .....?
#19. Zero power factor method for an alternator is generally used to determine....?
#20. Damper windings in alternator is to.....?
#21. For parallel operation, alternators must have the same?
#22. Most commonly used alternator is......?
#23. Cylindrical rotor alternators use ....... ducts for efficient cooling?
#24. Skew of rotor bar is to eliminate....?
#25. The stator of modern alternators are wound for ..... phase groups?
#26. The stator poles of an alternator is ......as rotor poles?
#27. Turbo alternators generally used....type rotor?
#28. A 3 phase delta connected alternator having a rotating armature will have...?
#29. The speed of a 6 pole, 60Hz alternator is....?
#30. At no loaded condition, the terminal voltage per phase of alternator is ...... to the generated voltage per phase?
#31. Calculate the pitch factor for a winding having 36 slots 4 poles with a coil span of 1 to 8?
#32. The effect of armature reaction in an alternator depends on the....?
#33. Terminal voltage of an alternator increases with the load when the power factor is.....?
#34. Alternator said to be over excited when it is operating at.....?
#35. The power factor of an alternator is determined by.....?
#36. In cylindrical rotor..... portion of rotor is wound?
#37. The angle between induced emf and terminal voltage on no load for a single phase alternator is....?
#38. The effect of leading powerfactor on the voltage regulation of an alternator is.....?
#39. Which method gives more accurate voltage regulation of an alternator?
#40. Which method gives higher than actual value of regulation of an alternator?
#41. In alternator, the leading powerfactor of terminal voltage ...... with load?
#42. When the load is removed from an AC generator, its terminal voltage rises from 480V at full load to 660 V at noload. calculate the voltage regulation?
(660-480)/480 = 37.5
#43. The regulation of an alternator is positive when the power factor is....?
#44. Regulation of an alternator supplying resistive or inductive load is.....?
#45. At leading power factor, an alternator.....?
#46. What is the cause for hunting effect in alternators?
#47. What is the purpose of using damper winding in AC generator?
#48. What is the use of synchroscope?
#49. The number of slip rings in a rotating field system type alternator is.....?
#50. The rpm of turbo alternator has…?
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