Definitions1. DCseriesmotorhashighstartingtorque.2. Formostof theapplicationsDCshuntgeneratorismorepopularthanDCseriesgenerator.

3. Aseriesgenerator isprovidedwithdivertersandis diverting its rated current. Now if divertersswitch is opened, the terminal voltage willincrease.

4. Whenloadisremoved,aseriesDCmotorwillrunatexcessivelyhighspeed.

5. ThespeedofseriesDCmotordecreasesifthefluxinthefieldwindingincreases.

6. ThedirectionofrotationofaDCseriesmotorcanbe reversed by interchanging the field terminalonly.

7. Connecting a resistance in serieswith the fieldwinding, the speed of a DC shuntmotor can beincreasedabovetheratedspeed.

8. When starting a differentially connectedcompoundmotor,itisdesirabletoshortcircuitthe

series field winding to avoid excessive startingspeed.

9. During the normal operation of seriesmotor, ifthe fieldcircuit suddenlyopens, themotor speedwillincrease.

10. Series motor has high starting torque, shuntmotor has constant speed, 3phase inductionmotorhas lowerstarting torqueandsynchronousmotorhasverypoorstability.

11. If series field in cumulatively compound motorget shortcircuited then armature current andspeedwillbothincrease.

12. The serieswinding of a cumulatively compoundDCmotor isshortcircuitedwhiledrivinga loadatrated torque. This results in increase in both thearmaturecurrentaswellasmotorspeed.

13. In a differentially compoundDCmotor, if shuntfieldsuddenlyopens,themotorwillfirststopandthenruninoppositedirectionasseriesmotor.

14. Seriesmotorhaspoorestspeedregulation.

15. DCseriesmotor isused inbuses,trains,trolleys,hoists and cranesbecausehigh starting torque isrequired.

16. As the load is increased, the speedofDC shuntmotorwillreduceslightly.

17. ThespeedofDCmotorcanbevariedbyvarying:(i)fieldcurrent,(ii)appliedvoltage,(iii)resistanceinserieswitharmature.

18. SpeedcontrolmethodsofshuntDCmotorare:(i)fluxcontrolmethod,(ii)Armaturecontrolmethod,(iii)Voltagecontrolmethod

19. SpeedcontrolmethodsofseriesDCmotorisfluxcontrolmethodand its typesare: (i) fieldcontrol,(ii) Armature diverters, (iii) tapped field control,(iv)parallelfieldcoils

20. IfexcitationofDCshuntmotorischanged,torquewillchange,butpowerwillremainconstant.

21. Seriesmotorshouldnotbestartedatnoload.

22. A seriesmotorwillbepreferred for loadhavingpeak value for short short duration and almostzeroformostpartofthetime.

23. Series DC motor, as compared to shunt andcompoundmotor,hashighest torqueat the startbecause of its comparatively strong series field.And if load is removed then itwill runathighestspeed.

24. If the speed of shunt DC generator is doubledkeepingfluxconstant,itsgeneratedEMFdoubles.

25. Electromagnetic torque and speed are inopposite directions in the case of shuntgenerators.

26. WhenthesupplyterminalsofDCshuntmotorareinterchanged, the motor will run at its normalspeedinthesamedirectionasbefore.

27. IfpolarityofconnectionofthearmatureandfieldwindingarereversedsimultaneouslyinaDCshuntmotor,thenitwillrotateinthesamedirection.

28. If a DC shuntmotor is runningwith a certainload.Theeffectofaddinganexternalresistanceinthefieldcircuitistoincreasethemotorspeed.

29. If the applied voltage of a DC shunt motor ishalvedwith the load torque doubled, the speedwillbethesameandarmaturecurrentisdoubled.

30. A shuntmotor is running at its rated speed onrated load. If the field circuit gets suddenlyopened, themotorwill draw very high armaturecurrentbut itwill continue todrive the loadatareducedspeed.

31. SpeedofDCshuntmotorhasnothingtodowithapplied voltage if losses and saturation areneglected.

32. IfaDCshuntmotor isworkingatnoloadand ifshuntfieldcircuitsuddenlyopens,thiswillresultinexcessivespeed,possiblydestroyingarmatureduetoexcessivecentrifugalstresses.

33. As the load of shuntDCmotor is increased, itsspeedreducesslightly.

34. ThehighestspeedattainedbyaDCshuntmotoratratedfluxisequaltonoloadspeed.

35. If the speedofaDC shuntmotor increased, thebackemfincreases.

36. A shuntDCmotorhashighest%age increase ininputcurrentforagiven%ageincreaseintorque.

37. AshuntDCmotorhasapprox.constantspeed.38. Ifthesupplyvoltagetoashuntmotorisincreasedby25%,thefullloadspeedwilldecrease.

39. ADC shuntmotor has external resistance inthe field circuit& in thearmature circuit.Thestarting armature current for motor will beminimum,when isminimum& ismaximum.

40. Shunt motor with commutating poles has theleast reduction in speed from no load to ratedload.

41. If the field circuitof shuntDCmotor runningatratedspeedgetsopencircuited,thenimmediately,speedofmotortendtoincrease.

42. If the supplyvoltageofDC shuntmotor runningatratedspeed,ratedsupplyvoltageishalved,thenthespeedofthemotorbecomesslightly lessthantheratedspeed.

43. DirectionofDCshuntmotorwillremainthesameifboth the field terminals and armature terminalareinterchanged.

44. Difference between the no load and full loadspeedofaDCshuntmotorisoftheorderof1%.

45. In a DC shunt motor if the supply voltage isreducedby15%,fullloadspeedwillincrease.

46. ThefieldwindingofanunloadedDCshuntmotorgetsopenedwhilerunning,thenitwillstop.

47. ThespeedofDCshuntmotorcanbeincreasedbyincreasingtheresistanceinfieldcircuit.

48. If thespeedofDCshuntmotor is increased, thebackemfofrotorwillalsoincrease.

49. IfaDCshuntmotor isworkingatfull loadand ifshunt field suddenly opens, this will make

armature to takeheavy current,possiblyburningit.

Armature50. The part which houses the conductors and inwhich emf induced is to be utilized is calledarmatureinanyrotatingmachines.Or

51. The rotating part of aDCmachine is known asarmature.

52. All rotating electrical machines have rotatingarmatureandfixedfield.

53. The armature reaction in a DC motor isattributedtotheeffectofmagneticfieldsetupbyarmature current. In DC machine, the armaturereactionMMFisstationaryw.r.t.thestator.

54. The armature current drawn by DC motor isproportionaltotorquerequired.

55. Armature control method provides a constanttorquedrive.

56. If be thearmature current, then speedofDCshuntmotorisproportionalto

57. The armature voltage control of DC motorprovidesconstanttorquedrive.

58. InaDCmachine,ifPisthenumberofpoles,Nisthearmaturespeed inrpm then the frequencyofmagneticreversalwillbePN/120.

59. To get a strong magnetic field, the air gapbetween stator and armature is kept as small aspossible.

60. Armature flux leakage depends on: (i) length ofairgap,(ii)shapeofmagnetcore,(iii)fluxdensityusedincoreandteeth.

61. Starter resistance inaDCmotor isconnected inserieswiththearmature.

62. Plugging of DC motors is normally done byreversingthearmaturepolarity.

63. Factors responsible for decrease in terminalvoltage of DC shunt generator are: (i) Armatureresistance, (ii)Armaturecurrent, (iii)Reduction infieldcurrent.

64. The armature torque of the DC shuntmotor isproportionaltoarmaturecurrentonly.

65. ThespeedcontrolmethodofDCmachinewhichoffers minimum efficiency is armature controlmethod.

66. DC generators generate AC voltage in thearmature.

67. Armature core is made of silicon steel in DCmachines.

68. Commutator

69. Each commutator segment is connected to thearmatureconductorbymeanofcopperlug.

70. CommutatorofaDCmachineactsasafullwaverectifier.

71. A DC motor can be easily identified bycommutator.

72. The compensating winding is located on poleshoe for avoiding the flashover at commutatorsurface.

73. Sparking at the commutator of DC motor mayresult in: (i)damage to commutator segment, (ii)damage to commutator insulation, (iii) increasedpowerconsumption.

74. Constanttorque isproducedduetocommutatorinDCmotor.

75. Number of commutator segments is equal tonumberofarmaturecoilsinDCmachine.

76. Ripples indirectemfgenerated inDCgeneratorsarereducedbycommutatorswithlargenumberofsegments.

Interpoles1. If DC machine has interpole as well ascompensatingwindings, thenbothare connectedinparallelwitharmaturewindings.

2. For reducing sparking at the commutator,interpolesareusedinDCmotors.

3. FunctionoftheinterpolesintheDCgeneratorsisto neutralize cross magnetizing effects of thearmaturereaction.

4. The brushes on commutator remain in contactwithconductorwhichliesunderinterpoleregaininDCgenerators.

5. Interpoles winding is connected in series witharmaturewindinginDCgenerators.

6. In DC generators interpole field coils areconnected in series with armature winding.Interpoleshelpsthecommutationprocess.

7. If residual magnetism of a shunt generator isdestroyed accidently, it may be restored byconnectingitsshuntfieldtoabattery.

8. The sole purpose of commentator in a DCgenerator is to convert the induced alternatingvoltageintounidirectionalpulses.

9. All rotating electric machines are basicallyelectromechanicalconverters.

10. VB=E is the equation of the electricalmachinewhich convertsmechanical energy into electricalenergy.

11. Themaximumnumberofbrusheswhichmaybeusedinanelectricalmachineisequaltoeither2ornumberofpoles.

12. ADCgeneratorhas6poles.Aphysicalbrushshiftof 6degreemeans as electricalbrush shiftof 18degree.

13. ForsatisfactorycommutationofDCmachinesthebrushes shouldbe: (i)ofproper grade& size, (ii)smoothly run in the holders, (iii) smoothconcentricandproperlyundercut

14. Brushes forcommutators for220VDCgeneratoraregenerallymadeofelectrographite.

15. With the help of brushes & commutators, theunidirectionaltorqueisproducedinaDCmotor.

16. Thenumberofbrushes incommutatorsdependsonamountofcurrenttobecollected.

17. Voltage drop is the least in metal graphitebrushesinDCmachines.

18. InaloadedDCgeneratorifthebrushesaregivena shift from the interpole axis in thedirectionof

rotation, then the commutation will deterioratewhichwillresultinfallofterminalvoltage.

19. Theyoke inasmallDCmachine ismadeofcastiron.

20. The yoke of DC machine is always made ofmagneticmaterial.

21. Compensatingwinding inaDCmachine isplacedonyokeinthepolefaces.

Losses22. Hysteresis losses inaDCgeneratorarebasicallydue to reversal of magnetism of the armaturecore.ItisproportionaltoN,f

23. Windage loss is proportional to square ofarmaturespeedinaDCgenerator.

24. Iron losses in a DC machine take place inarmaturerotor.

25. Core losses in a DC machine occur in botharmatureandpolefaces.

26. The efficiency of a DC shunt generator ismaximum when the armature copper losses areequaltoconstantlosses.

27. Armature copper loss is likely to have highestproportionoflossesinDCgenerator.

28. Armature copper loss varies significantly withloadcurrentinDCgenerator.

29. Usingmaterial of low hysteresis coefficient forarmaturecorematerialwillresultinlowhysteresislosses.

30. IronlossesinDCgeneratortakeplaceinarmaturerotor.

31. Brush contact loss depends on loadwhile strayloadlossesdependonsquareofload.

32. Eddy current losses in a DC machine areproportionalto , .

33. HysteresislossinaDCmachineisgivenby . whereVisthevolumeofironpart.

34. A DC machine has maximum efficiency whenvariablelossesareequaltoconstantlosses.

35. In DC machines, constant loss is composed offrictionWindageandironlossandfieldcircuitloss.

36. If a DC generator operates at constant speed,variable loads then the losses which would bemostsignificantarecopperlosses.

37. IronlossesoccurintheyokeinDCmotor.38. In DC machines,maximum losses occur due tocopperlosses.

39. Hysteresis and eddy current losses depend onfluxmagnitude.

40. Noload rotational losses depend on rotorrotation.

41. In DC generator mechanical losses have leastproportion.

42. Ironlossescauseexcessiveheatingofcore,riseintemperatureandlowefficiency.

43. If t is the thickness of lamination then eddycurrentlossingeneratorareproportionalto

44. If is themaximum flux density then eddycurrentlossisproportionalto

45. The hysteresis loss is proportional to fwhich isfrequencyofmagneticreversalinDCgenerators.

46. CopperlossvarieswithloadinDCgenerator.47. Windagelossdoesntvarywithloadnorwithfluxdensity.

48. Mechanical loss, core loss and copper lossdissipateintheformofheat.

49. Eddy current loss are significantly reduced bylaminatingthecoreofDCgenerator.

50. TotallossesinawelldesignedDCgeneratorof10kWwillbenearly500W.

51. Mechanicallossesareprimaryfunctionofspeed.52. Ironlossesareindependentofloadvariation.53. Sumof iron lossesandmechanical loss is calledstraylossinDCmachine.

DifferentTests54. Hopkinsons test is a usefulmethod for testingtheefficiencyofDCmachine.

55. Swinburnetest isthemosteconomical infindingthenoloadlossesofalargeDCshuntmotor.

56. To determine the stray losses in case of shuntmotors&generatorsretardationtestisused.

57. Backtoback test on DC machines needsminimumoftwomachines.

58. HopkinsonstestonDCmotorisconductedatfullload.

59. InWard Leonardmethod of speed control, theminimumnumberofmachineneededisthree.

60. WardLeonardcontrol isbasicallyvoltagecontrolmethod. Itsdisadvantageare:high initialcost, (ii)highmaintenance cost, (iii) lowefficiencyay lightload

61. Fieldstestcanbeconductedonotherthanshuntmachines.

62. OnlyonemotorisrequiredinBraketest.63. Swinburnetestcannotbeusedforseriesmotors.64. Retardation test isused to find the stray loss inshuntDCmachines.

65. Field testwillbe suitable for testing two similarDCmotorsoflargecapacity.

66. ThemaindisadvantageofHopkinsonstestisthatitrequirestwoidenticalshuntmachines.

67. WardLeonard system of speed control is notrecommendedforconstantspeedoperations.

68. BrakingtestonDCmotorsisusuallyrestrictedtosmallHPmotors.

...1. Polarity of DC generator can be reversed byreversing field current and also the direction ofrotation.

2. In DC generator relation between commercialefficiency , electrical efficiency andmechanicalefficiency isgivenby = .

3. When paralleling of two compound generatorsare needed then equalizer connections arerequired.

4. The function of a starter in aDCmachine is toavoidexcessivecurrentatstarting.

5. AcumulativelycompoundDCgeneratorsupplies15A at 240V. Now if the series field winding isshort circuited, the terminal voltage will reducebelow240V.

6. In a DCmachine, torque and induced EMF areproducedbothinmotorandgenerator.

7. ThemechanicalpowerdevelopedbyaDCmotorismaximumwhen the back EMF is equal to halftheappliedvoltage.

8. A selfexcited DC shuntmotor is running at noload at 1000 rpm. If the terminal voltage isreduced 50% of its original value, the noloadspeedoftherotorwillbe1000rpm(same)

9. TherotoriskeyedtotheshaftinDCmotor.10. If DC series motor having rating of 230V isconnected to AC supply of 230V then itwill runwithlessefficiency.

11. Direction of induced EMF can be found byapplyingFlemingsrighthandrule.

12.

13. The ratio of back EMF to supply EMF is anindicationofefficiencyofDCmotor.

14. ThevoltageequationofDCmotorisV= + 15. MaximumpowerisachievedinaDCmotor,whensupplyvoltageisequaltodoubleofbackEMF.

16. ThespeedofaDCmotor isdirectlyproportionaltobackEMF.

17. A150VDCmotorwithback142Vhas armatureresistance1,thenarmaturecurrentis8A.

18. Keepingloadcurrent&fluxofDCmotorconstantifvoltageappliedacrossarmatureisincreased4%,thespeedofmotorwillincreaseby4%.

19. A DC motor develops a torque off 100Nm at1000rpm.Now ifrpm is1200thentorquewillbe120Nm.

20. The starting resistance of DC motor is usuallysmall.

21. The back emf of a DCmotor depends on fieldflux.

22. When the direction of power flow reverses, acumulatively compound motor becomes adifferentiallycompoundgenerator.

23. Theoutputpowerofanyelectricalmotoristakenfromthecouplingmountedontheshaft.

24. If the field current is reduced to half, keepingconstant torque load& rated excitation then thespeed of motor will become slightly less thandouble.

25. A DCmotor draws high current at the time ofstartingbecause =0(backemf).

26. A10HPseriesDCmotorusesadivertertocontrolthe speed.Fora constant load torque, the speedwill beminimumwhen the diverter resistance isinfinite.

27. TwoDC seriesmotors connected in seriesdrawcurrentIfromsupplyandrunatspeedNwhenthesametwomotorsareconnected inparalleltakingcurrentIfromthesupply,thespeedofeachmotorwillbe4N.

28. The starter for a DC motor also providesprotectionagainstdamage: (i)duetoshortcircuitintheequipment,(ii)fromlongtermoverload,(iii)fromexcessivestartingcurrents.

29. DirectonlinestartersarenotsuitableforstartinglargeDCmotors because large voltage dropmayoccurinthesupplymains.

30. Thedirectionof rotationof themotor isusuallyreversed by revering the connection of thegeneratorfieldterminalsinWardLeonardmethod.

31. The most economical method of electricalbrakingofDCmotorisregenerativebraking.

32. Regenerative braking in shunt motors is usedwhentheloadhasoverhaulingcharacteristics.

33. Thenominalpowerprintedonthenameplateofanymotorsignifiestheoutputpowerattheshaft.

34. InanoverloadDCmotor,maindangerarisesduetooverheatingofwindings.

35. The maximum permitted temperature in DCmotorwindingsisusually40degreeto50degree.

36. The generated emf and the current are in theoppositedirectionincaseofDCmotors.

37. Steppermotorisusedindigitalcontrolsystem.38. Universal motor is used in hand drills, singlephase inductionmotor isuse inceiling fanswhileincassettetapePMDCmotorisused.

39. A4poleDCgeneratorisrunningat1500rpm,thefrequencyofcurrent inthearmaturewouldbe50Hz.

40. Speedcontrolbyvariationof field flux results inconstant power drive while speed control byvarying the armature circuit resistance offersconstanttorquedrive.

41. The relation between electrical ( ) andmechanical ( )degree isgivenby: = (P/2) wherePrepresentspolesofmachine.

42. ADCcumulativelycompoundgeneratorwhich issupplying power to infinite bus will becomedifferentially compoundmotorwith the direction

andspeedsame ifmechanicalpowersupply formtheprimemoverfails.

43. ADC shunt generator builds up to a voltage of220Vatnoloadwhilerunningatitsratedspeed.Ifthespeed israisedby25%,thenvoltagewillbuilduptolevelbetween220V&1.25timesof220V.

44. TwoidenticallosslessseriesmotorsconnectedinseriesacrossaDC supplyvoltage runat speedof& .Thentheratiooftheiroutputpowerswill

be : 45. In DC machine, the field system has to beprovided on stator, unlike synchronous machinewhereinitcouldbeonanymember.

46. A 2 pole series motor with its two field coilsconnected in series runs at a speed of 500 rpm.Now if field coils are reconnected inparallel andassumingthattorqueisconstantandthemagneticcircuit isunsaturated,thenewspeedwillbe1000rpm.

47. Laws of electromagnetic induction (Faraday andLenzs)aresummarizedin:e=d/dt.

48. In armature controlled separately excited DCmotor drive with closedloop speed control, aninner current loop is useful because it limits thepeakcurrentofthemotortothepermissiblevalue.

49. Anelectricmotorwithconstantoutputpowerwillhave torquespeedcharacteristics in the formofarectangularhyperbola.

50. The efficiency ofmotor operating at 1500 rpmanddrawingcurrent3.5Awitharmatureresistanceof0.8andnoloadcurrent1.5Aat25Vis48%.

51. For same HP rating and full load speeddifferentially compound motor has poor startingtorque.

52. If the supply voltage forDCmotor is increased,full loadcurrentwilldecrease.Operatingspeedorstartingtorquewillnotdecrease.

53. Air gap in DC motor is more than inductionmotor.

54. InvariablespeedoperationDCmotorispreferredoverACmotor.

55. Beforesaturation inDCmotor where istorque& isarmaturecurrent.

56. DCmotorisusedwherehighstartingtorqueandwidespeedrangecontrolisrequired.

57. The speed ofmotor falls from 1100 rpm at noload to 1050 rpm at rated load. The speedregulation of the motor is (11001050)/1050=1/21=4.76%

58. Thespeed regulationofDCmotor is:= (No loadspeedfullloadspeed)/fullloadspeed

59. If back emf and speed both are doubled, thetorqueremainsunchanged.

60. At the instantofstarting,whenDCmotor isputonsupply,itbehaveslikelowresistancecircuit.

61. DC series motors are not used where load isconstant or frequency changing or constantoperatingspeedisrequired.

62. IfterminalsofDCmotorareinterchanged,thisiscalledpluggingbrakingwhichgiveshighesttorquebraking.

63. Thyristor can be used to control the speed ofmotor.

64. DC series machine has field consisting of fewnumberofturnsofthickwire.

65. Torque developed in DCmotor depends on: (i)magnetic field, (ii) Active length and number ofconductors, (iii) current flow through theconductors

66. DC generators are designed for maximumefficiencyaroundfullload.

67. DCgeneratorsare installednear load centers toreducecoronalosses.

68. Dynamic braking is generally used for shunt,seriesandcompoundmotors.

69. A weaker commutating field is needed at lowspeedthanathighspeedinvariablespeedmotor.

70. ThemechanicalpowerdevelopedbyDCmotorisequal to product of back emf and armaturecurrent.

71. The variable resistor shunting the field of a DCseriesmotoriscalledafielddiverter.

72. InBraketestonlyonemotorisrequired.73. Low cost isnot an advantageofDCmotoroverAC.

74. The function of field regulators for compoundmotorsistocontroltheflux.

75. Motor is made to run as generator inregenerativebraking.

76. InducedemfisgivenbyBlvwhereB=fluxdensity,l=lengthofconductor,v=velocityofconductor.

77. For generating large currentsonDC generators,Lapwindingisgenerallypreferred.

78. The purpose of providing dummy coils in thegenerators is to provide mechanical balance fortherotor.

79. Reversing the field current, the polarity of DCgeneratorcanbereversed.

80. The maximum number of equalizers rings are2Z/P in lapwoundDCgeneratorwhereZ=numberofconductor,P=numberofpoles

81. EddycurrentareinducedinthepoleshoeofaDCmachineduetorelativerotationbetweenfieldandarmature.

82. Equalizer rings are required in case armature inlapwound.

83. InDCmachine,shortcircuitedfieldcoilwillresultin: (i)odourofburning insulation, (ii)unbalancedmagneticpull,producingvibrations, (iii) reductionof generated voltage, forwhich excitation has tobeincreasedtomaintainthevoltage.

84. Compensatingwindinghelpincommutation.85. InDCgenerators themagnetic field isproducedbyeitherelectromagneticorpermanentmagnet.

86. For lowvoltage,highcurrent lapwinding isusedinDCgenerators.

87. ActualfluxdistributioninDCgeneratorsdependson : (i)sizeofairgap, (ii)shapeofpoleshoe, (iii)clearancebetweentipsoftheadjacentpoleshoes

88. DC series generator is used as booster tomaintain constant voltage at the load endof thefeeder.

89. Thenumberofmechanicaldegreeandelectricaldegreewillbethesamewhennumberofpolesis2intheDCgenerators.

90. Permanenceisthereciprocalofreluctance.91. Theemf generated inaDC generator isdirectlyproportional to : (i) flux/pole, (ii) speed ofarmature,(iii)numberofpoles

92. When there is no load on generator, themagnetic neutral axis coincides with thegeometricalneutralaxis.

93. If shunt generator at 1000 rpm has emf 200V,then at 1200 rpm, the emf would be 240V i.e.directrelation.

94. IfaDCgenerator fails tobuildup, theprobablecause could not be field resistance less than thecriticalresistance.Anditcouldbeimperfectbrushcontacts,faultshuntconnectiontendingtoreducethe residualmagnetismorno residualmagnetisminthegenerator.

95. If emf induced in armature is 600V in shuntDCgenerator. Armature resistance is 0.1 andcurrentis200Athenterminalvoltageis580V.

96. In DC generator, the critical resistance is theresistanceoffield.

97. The reason of short circuit in armaturewindingcould be: (i) insulation failure between twocommutators bars, (ii) insulation failure betweentwo turnsofa coil, (iii) twoormore turnsof thecoilgettinggrounded

98. Number of tapping for each equalizer ring isequaltonumberofpolepairs.

99. A DC generator can be considered as rotatingamplifier

100. Lapwinding iscomposedofanyevennumberofconductors.

101. IfresistanceoffieldwindingisincreasedinDCgenerator,thentheoutputvoltagewilldecrease.

102. Voltage remains constant irrespective of theloadinflatcompoundgenerator.

103. Anequalizerbar isusedwhen twoDC seriesgeneratorsarerunninginparallel,sothatmachinepassesapprox.equalcurrenttotheload.

104. Shunt generators are preferred for paralleloperation.

105. A DC generator work on the principle ofFaradayslowofelectromagneticinduction.

106. A series generator can selfexcite only if theloadcurrentisnotzero.

107. A shunt generator can selfexcite only if theresistance of the field circuit is less than criticalvalue.

108. Terminalvoltageofaseriesgeneratoris150Vwhen load current is 5A. If load current is 10A,thenterminalvoltagewillbegreaterthan150V.

109. If the open circuit voltage of a compoundgenerator is 250V, then at full load the terminalvoltagemaybegreaterorlessthan250V.

110. In case of DC generator 1% regulation isusuallypreferred.