1) In generators, what principle is used to convert mechanical motion to electrical energy?a) Atomic reaction b) Electrical attractionc) Magnetic repulsion d) Magnetic induction

2) When you use the left-hand rule for generators, what is indicated by the middle finger?a) Direction of flux b) Direction of motionc) Direction of current flow d) Direction of the magnetic field

3) The output voltage of an elementary generator is coupled from the armature to the brushes by what devices?a) Slip rings b) Interpolesc) Terminals d) Pigtails

4) An elementary generator consists of a single coil rotating in a magnetic field. Why is NO voltage induced in the coil as it passes through the neutral plane?

a)Flux lines are too dense b) Flux lines are not being cutc) Flux lines are not present d) Flux lines are being cut in the wrong direction.

5) What components cause(s) a generator to produce a dc voltage instead of an ac voltage at its output?a) The brushes b) The armature c) The slip rings d) The commutator

6) When two adjacent segments of the commutator on a single-loop dc generator come in contact with the brush at the same time, which of the following conditions will occur?

a) The output voltage will be zerob) The output voltage will be maximum negativec) The output voltage will be maximum positive

7) In an elementary, single-coil, dc generator with one pair of poles, what is the maximum number of pulsations produced in one revolution?

a) One b) Two c) Three d) Four

8) If an elementary dc generator has a two coil armature and four field poles, what is the total number of segments required in the commutator?

a) 8 b)2 c) 16 d) 4

9) How can you vary the strength of the magnetic field in a dc generator?a) By varying the armature currentb) By varying the speed of armature rotationc) By varying the voltage applied to the electromagnetic field coilsd) By varying the polarity of the field poles

10) Under which of the following conditions does sparking occur between the brushes and the commutator?a) When operating under normal conditions b) When there is improper commutationc)When there is an excessive load current d) When commutation is in the neutral plane

11) Distortion of the main field by interaction with the armature field defines what term?a) Commutation b) Mutual reaction c) Armature reaction d) Mutual induction

12) Distortion of the main field by interaction with the armature field can be compensated for by the use ofa) slip rings c) interpolesc) a commutator d) special brushes

13) Motor reaction in a dc generator is a physical force caused by the magnetic interaction between the armature and the field. What effect, if any, does this force have on the operation of the generator?

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a) It tends to oppose the rotation of the armature b) It tends to aid the rotation of the armaturec) It causes the generator to vibrate d) None

14) In dc generators, copper losses are caused by which of the following factors?a) Reluctance in the field poles b) Resistance in the armature windingc) Reactance in the armature and field windings d) All of the above

15) Eddy currents in armature cores are kept low by which of the following actions?a) Using powdered iron as a core material b) Limiting armature currentc) Insulating the core d) Laminating the iron in the core

16) What makes the drum-type armature more efficient than the Gramme-ring armature?a) The drum-type armature has more windings than the Gramme-ring armatureb) The drum-type armature can be rotated faster than the Gramme-ring armaturec) The drum-type armature coils are fully exposed to the magnetic field, while the Gramme-ring armature coils are only partially exposed to the magnetic fieldd) The drum-type armature has a laminated core, while the Grammering armature has a solid core.

17) Which of the following is NOT a major classification of dc generators?a) Compound-wound b) Series-woundc) Shunt-wound d) Lap-wound

18) What characteristic of series-wound generators makes them unsuitable for most applications?a) They require external field excitationb) The output voltage varies as the speed variesc) They are not capable of supplying heavy loadsd) The output voltage varies as the load

19) When two or more generators are used to supply a common load, what term is applied to this method of operation?

a) Series b) Compound c) Split-load d) Parallel

20) When you use the right-hand rule for motors, what quantity is indicated by the extended forefinger?a) Direction of flux north to south b) Direction of flux south to northc) Direction of current d) Direction of motion

21) What determines the direction of rotation of a dc motor?a) The type of armature b) The method of excitationc) The number of armature coils d) The polarity of armature current and direction of magnetic flux

22) Which, if any, of the following situations is a major electrical difference between a dc motor and a dc generator?

a) The armatures are differentb) The shunt connections are differentc) The dc generator requires a commutator, the dc motor does notd) None of the above

23) In a dc motor, what causes counter emf?a) Improper commutation b) Armature reactionc) Generator action d) Excessive speed

24) In a dc motor, how, if at all, does counter emf affect speed?a) It causes the speed to increase b) It causes the speed to decreasec) It causes rapid fluctuations of the speed d) It does not affect speed

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25) What is the load on a dc motor?a) The field current b) The armature currentc) The mechanical device the motor moves d) The total current drawn from the source

26) When a series dc motor is operated without a load, which of the following conditions occurs?a) The armature draws excessive current b) The voltage requirement increasesc) The armature will not turn d) The armature speeds out of control

27) A dc series motor is best suited for which of the following applications?a) Steady load, low torque b) Variable load, low torquec) Steady load, high torque d) Variable load, high torque

28) What is the main advantage of a shunt motor over a series motor?a) A shunt motor develops higher torque at lower speeds than a series motorb) A shunt motor can be operated at higher speeds than a series motorc) A shunt motor draws less current from the source than a series motord) A shunt motor maintains a more constant speed under varying load conditions than a series motor

29) How can the direction of rotation be changed in a dc motor?a) Only by reversing the field connectionsb) Only by reversing the armature connectionsc) By reversing both the armature connections and the field connectionsd) 4.By reversing either the armature connections or the field connections

30) When the voltage applied to the armature of a dc shunt motor is decreased, what happens to the motor speed?

a) It becomes uncontrollable b) It decreasesc) It increases d) The motor stops

31) In a dc motor, the neutral plane shifts in what direction as the result of armature reaction?a) Clockwise b) Counterclockwisec) In the direction of rotation d) Opposite the direction of rotation

32) Magnetic induction in an alternator is a result of relative motion between what two elements?a )The rotor and the armature b) The armature and the fieldc )The field and the stator d) The rotor and the field

33) Voltage is induced in what part of an alternator?a) The commutator b) The brushes c) The armature d) The field

34) Alternators are rated using which of the following terms?a )Volts b) Watts c)Amperes d) Volt-amperes

35) Which of the following motors is/are types of ac motor?a) Series b) Synchronous c) Induction d) All of the above

36) Which of the following types of motors is widely used to power small appliances?a) Universal b) Synchronous c) Polyphase d) Compound

37) What type of ac motor is most widely used?a) Series b) Universal c) Synchronous d) Single-phase induction

38) What type of ac motor uses a combination of inductance and capacitance to apply out-of-phase currents to the start windings?

a) Three-phase b) Series c) Synchronous d) Split-phase induction

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39) The speed of the motor can be varied by ___.a) Changing supply frequency b) Changing no. of polesd) ) Using multi speed windings d) All the above

40) The type of single-phase induction motor having the highest power factor at full load isa) shaded pole type (b) split-phase type(c) capacitor-start type (d) capacitor-run type

41. Calculate the percentage of regulation of generator with a no load voltage of 462 volt and full load volt. 440 Va. 150% b. 105% c. 5% d. 95%

42. At what point should brush contact change from one commutator segment to the nexta. a full positive voltage b. at full negative voltagec. at MNA d. at GNA

43. Copper losses increase as:a. voltage increases b. current increasesc. square of current d. square of the resistance

44. Total number of commutator segment is equal to:a. equal the number of field coil b. equal the number of armature turnc. equal the twice of armature loop d. equals the twice of armature conductor

45. In motor moves in same direction as the rotating stator field due to:a. flaming left hand rule b. right hand rulec. grip rule d. lenz law

46. In capacitor start induction motora. starting winding is connected in parallel with main windingb. starting winding is connected in series with main windingc. starting winding is connected in parallel with auxiliary windingd. auxiliary winding is connected in parallel with main winding and is placed physically at right angle

47. In capacitor start I.M.a. in capacitor circuit current leads 90o by voltageb. in capacitor circuit voltage leads 90o by currentc. in capacitor circuit current leads the line voltage by 45o

d. in capacitor circuit current lags the line voltage by 45o

48. In capacitor start IMa. capacitor is connecting in series with main field windingb. capacitor is connecting in parallel with starting windingc. capacitor is connecting in series with starting windingd. capacitor is connecting in series with rotor winding

49. Synchronous motor has the disadvantage of requiringa. a.c. exciter voltage for stator b. d.c. exciter voltage for statorc. a.c. exciter voltage for rotor

50. Flashing the field meansa. momentarily passing current through field coils in same way as normally flowsb. passing current through field coils in opposite way as normally flow for long periods

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c. momentarily passing current through field coils in opposite way as normallyd. either a or d.

51. Advantage of brushless alternator over a.c. generatora. low maintenance cost b. brushes & slip ring are eliminatedc. better performance at high altitude d. all

52. Essential part of brushless generatora. main generator, exciter generatorb. main generator, permanent mag. Generatorc. exciter generator, permanent mag. Generatord. main generator, permanent mag. Generator, exciter generator

53. Shaded ring is present on pole of shaded pole motora. trailing edge of pole b. leading edge of pole c. center of pole

54. Slip is thea difference between actual rotor speed and synchronous speed in d.c. motorsb. difference between actual rotor speed and synchronous speed in a.c. motorsc. difference between actual rotor speed and synchronous speed in induction motord. all

55. In elementary d.c. generator, if number of coil is increaseda. induced emf will increaseb. number of ripple frequency will increase, resulting in steady d.c.c. ripple will decreased. both c. and d.

56. Generator control unit is capable of performinga. voltage regulation, over volt. Protection, reverse polarity protectionb. reverse current and differential voltage protection over volt. and under volt. protectionc. anti cycle protection, generator line contactor control flash and start relay controld. all

57. Direction of rotation of generator when viewed from the drive enda. clockwise b. anti clockwise c. either a. or b.

58. In a generator, what eliminates any possible sparking to the brush guides caused by the movement of brushes within the holder?a. the pigtail b. brush spring tensionc. under cutting the mica on commutator d. lubricating the brush sides

59. The level of compounding in cumulative compound d.c. generator is usually adjusted by:a. alternating series field b. changing shunt field currentc. connecting it long shunt d. connecting in short shunt

60. In vibrator type voltage regulator, relay contacts in each section i.e. (volt regulator, current regulator and RCCR) normally:a. close, open, close b. close, close, closec. close, close, open d. open, open, close

61. Generator with vibrator type voltage regulator and its O/P is fluctuate due to:a. pitting on contact point b. tension of adjustment spring is lowc regulating resistor burn d. all

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62. Vibrator type voltage regulator used for;a. high field current b. low field currentc. both a. and b. d. none

63. Two current carrying parallel conductor (in same direction)a. tends to repel b. tends to attract c. no result

64. Motor used for a.c. engine startinga. shunt motor b. induction motor c. series motor d. synchronous motor

65. Change the direction of rotation of shaded pole I.M.a. reversing the connection to starting windingb. reversing the connection to main windingc. either a. or b.d. none

66. Slip phase motor isa. not self starting b. self starting c. external excitation is required

67. A.C. series motora. also known as universal motor b. operated on d.c.c. not an induction motor d. all

68. When motor or generator operating properly……... indicatesa. knocking b. evenly hum c. armature dragging d. none

69. If RCCR contact (Reverse current cut out relay) contact points fail to open after the generator O/P has dropped below battery volt. current will flow through the generator armature:a. in the normal direction and through shunt field opposite the normal directionb. opposite the normal direction and through the shunt field in the same directionc. opposite in shunt field

70. Number of alternation in a/c. 400 Hz a. c.a. 200 b. 800 c. 400 d. 1600

71. In diagram generator is:a. series wound b. shunt wound c. compound wound

72. Sides of the loop moves parallel to line of fluxa. max. volt. induced b. volt. inducedc. max. positive volt. included d. max. negative volt. induced

73. The neutral plane is the position where the plane of the two opposite coil is:a. parallel b. at 45o c. perpendicular

74. Compensating windinga. connected in series with field windingb. connected in series with armaturec. as in b. and mag. field produced by compensating winding will aid to mag. Field produced by

armatured. as in b. and mag. field produced by compensating winding will counter race the mag. field

produced by armature.

75. Inter polesa. counter acts the effects of armature winding

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b. minimize field distortionc. as in a. and tends to keep the neutral plane in same position for all loadsd. all

76. If series field aids the shunt fielda. plane compound b. differentially compoundc. cumulative compound d. over compound

77. In electric arc welding….. generator is used:a. differential compound b. shunt c. cumulative compound

78. “coming in”: speed meansa. produced over volt. than rated volt. b. produced normal volt.c. produced very low volt. than rated.

79. Change the direction of rotation of single phase motora. reversing the connection to main windingb. reversing the connection to starting windingc. either a. or b.d. bother a. and b.

80. In a vibrator contact type voltage regulator is connected with generator output in a. series b. parallel c. series-parallel d. either a or b.

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