DC Generator Question & AnswersNovember 1, 2021 By Wat Electrical This article lists 100 DC generator MCQs for engineering students. All the DC generator Questions & Answers given below include a solution and link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up their fundamentals on the DC generator topic which is core in Electrical Engineering.Generators are separate electrical devices or machines, used to supply electricity once electricity from the nearby grid is not available. These are classified into two types based on their output like AC generators and DC generators.These generators play a key role by providing backup power to homes, businesses, industries, organizations when there is no power supply. The main function of Generators is to change the energy from mechanical or chemical into electrical. 1). For large DC loads, we connect DC generators in--------SeriesParallelStraight lineBoth a & cHintIn this connection, the flow of current will be in different paths 2). For connecting two DC generators in parallel they should have ---?Different voltage characteristicsSame Current characteristicsSame Drooping voltage characteristicsSame r.p.m.HintThey must have similar voltage characteristics 3). Lap windings in DC generators are used for---?High voltage and High currentHigh voltage and low currentLow voltage and High currentLow voltage and low currentHintFor maximum current and less voltage 4). For parallel connected Dc generators, the summation of the current carried by them is equal to---?Total Armature currentLoad currentApplied source valueAll of the above.HintThe current at electric load 5). For the DC generator, the resistance of ------is critical?Load.BrushesFieldShaftHintThe field resistance is critical 6). In an idle DC generator, the % of regulation is...?0%5%10%50%HintThe regulation is zero 7). The Field coils of the DC generator are made up of ----?SteelCopperAluminumIronHintThe chemical element of this material is Cu 8). The first electrical generator was invented by…?Michael Faraday'sAugust ToeplerParamahamsa TewariJohn ReadHintThe first electric generator name is Faraday disk 9). DC generators are categorized into ….. Types depending on the field excitation methods?2345HintThey are permanent magnets, self-excited & separately excited 10). The material used to make the core lamination is?CarbonCopperSilverSilicon steelHintThese are ferritic alloys of silicon & iron 11). If the generators are need to run parallel then which of the following type is used?Series generatorsPermanent magnetShunt generatorsCompound generatorsHintIn this type of generator, both the windings are connected in parallel 12). If the critical resistance of a DC generator is increased then…?Speed will be increasedSpeed will be decreasedSpeed resistance will be increasedSpeed resistance will be decreasedHintThe DC motor performance will be increased 13). Welding generator includes….winding?DeltaLapWaveDuplex WaveHintThis winding includes two layers 14). The armature winding’s resistance mainly depends on…?TemperatureVoltageCurrentNumber of conductors usedHint It includes electrons as charge carriers 15). Which of the following bearings are used to give support to the rotor shaft?BushBallNeedleMagneticHintIt is one kind of rolling-element bearing 16). The mechanical losses within DC generators are the main function of?VoltageCurrentResistanceSpeedHintThe operating speed of any generator is 1000rpm 17). The flow of current to the external circuit in a DC generator can be given through?Slip ringsCommutatorWindingsBearingsHintThe main function of this is to change the alternating current into pulsating direct current 18). The material used to make a brushless dc machine is?IronCopperAluminumCarbonHintThese materials are composed of carbon atoms 19). Which of the following material is used for commutator brushes?CarbonAluminumCopperIronHintThese materials have mainly various properties & structures. 20). When the armature is….wound then equalizer rings are necessary?LapWaveDuplexDeltaHintIn electrical machines, this winding includes two layers 21). Long shunt compound generator is used in automobiles for…?Battery chargingIncrease the performanceDecrease the performanceControl the speedHintThis generator is used to make the battery active in automobiles 22). A DC generator can be used like a…?RectifierRotating amplifierControlling devicePower pumpHintIt is also known as a dynamoelectric amplifier Please refer to this link to know more about DC Generators 23). The field resistance is the critical resistance of….?DC MotorDC GeneratorDC MachinesAC MachinesHintThey provide power continuously to power grids & electric storage instruments. 24). The working principle of dc generator is…?Ohms lawLenz’s lawFaradays induction lawLorentz forceHintIt is a basic law in electromagnetism 25). The regulation used in DC generators is?1%10%50%100%HintOnly one percent of regulation is usedDC Generator MCQs for Interviews 26). Which generator is used for long transmission line feeding?Flat compoundOver compoundSeriesShuntHintThese generators are also called cumulative compound generators 27). When a series generator is self-excited?If the current at load is zeroIf the current at load is not zeroIf the maximum current is there at loadIf the minimum current is there at loadHintWhen there is no current at load then the generator will be self-excited. 28). How the lamination of a DC generator can be done to…?Decrease the bulkBy insulating coreBy decreasing eddy current lossBy insulating the coreHintThese losses are undesirable within electrical machines 29). In a 4-pole DC machine, the direction of all the poles are…?South polesNorth polesFrom north to southAlternate poles are south & northHintIn four poles, alternate poles are south & north 30). In a DC generator, the generated emf is directly proportional to….?Armature speedFluxPoleWindingsHintIt generates a flow of current across the field 31). Which of the following generator’s terminal voltage changes when load changes?SeriesShuntSeries compoundShunt compoundHintThese types of generators are used as boosters 32). In which type of generator, the poorest voltage regulation is there?ShuntDifferential compoundedSeriesShunt compoundHintThis type of generator includes both the series & shunt windings 33). The connection of field windings in the separately excited generator is?Series with circuitSeries with sourceShunt with sourceShunt with circuitHintWindings are connected in series with the source 34). The brushes in DC generators are made with…?CopperBronzeCarbon & GraphiteSilverHintThe brushes are made with two materials 35). The connection of inter pole winding can be done in series with….winding?FieldWaveArmatureLapHintIn this winding, the conversion of power takes place 36). A DC shunt generator is an exciter for…?TurbogeneratorSeries generatorShunt generatorCompoundHintIt is used to connect the shaft in a steam turbine 37). In electrical machines, which of the following material is used to decrease hysteresis loss…?Cast ironSilicon steelTungsten steelAluminumHintIt is a ferritic alloy of silicon & iron 38). When the DC generator’s polarity is reversed, then,?Field current can be reversedIncreases field currentMotor speed will be increasedField current can be increasedHintThe flow of current toward the field windings in a generator 39). Lap winding is used in which machines?High current & high voltageHigh current & low voltageLow current & Low voltageLow current & Low voltageHintUsed in machines that have max current and min voltage 40). How is the magnetic field generated in DC generators?ElectromagnetsWindingsPermanent magnetsYokeHintThese are made with wire coils to allow the electricity supply 41). How many poles are there in small DC machines?2345HintPoles are electromagnets in DC machines 42). The most commonly used DC machines are…..?3 Pole4 Pole6 Pole8 PoleHintThe poles used in this machine are north poles 43). How many parallel paths are available in triplex wave winding…..?2456HintThese are found by multiplying the available poles with the number of rotations 44). The type of generator used for welding is.?Cumulatively compounded generatorSeries generatorShunt generatorDifferentially compounded generatorHintIn this type of generator, both the shunt and field windings are simply connected in reverse directions. 45). Stray loss within a DC machine is the sum of …… and …..?Copper & mechanical lossesMechanical & iron lossesIron & armature copper lossesMechanical & iron lossesHintThese losses mainly occur because of the motor’s movement and alternating flux within the transformer’s core. 46). Which of the following part provides DC for a DC generator?CommutatorEyeboltBrushesWindingsHintIt is a rotating electrical switch in many motors 47). In commutator segments, which of the following material is used?CopperMicaCarbonPaperHintMica is mainly used for electrical insulation 48). When dummy coils are used in a DC generator?To decrease eddy current lossesFor voltage amplificationTo improve flux densityFor providing mechanical balance to the rotorHintTo provide balance to the rotating part 49). Which of the following loss has the highest proportion within DC generators?Eddy current lossHysteresis lossField copper lossArmature lossHintThis is also called armature reaction or effect 50). Which loss will be changed with the load current in DC machines?Field copper lossWindage lossEddy current lossArmature copper lossHintThe loss of power like heat within the machine windingsDC Generator MCQs for Exams 51). What is the function of the fractional pitch in the DC generator?Increases voltageSparking can be reducedImproves coolingGives protectionHintIt protects the copper material so that sparking cannot occur 52). Why aluminum is not used as a winding within DC machines?It is not strongIt uses more spaceExpensiveLess resistivityHintAs compared to copper, aluminum cannot be used in a fixed space 53). What is the function of frog leg winding in a DC machine?It eliminates the compensating windingIt eliminates equalizers within the windingReactance voltageControls the machine speedHintIn the lap winding of DC machines, it avoids the distribution of unequal current. 54). In a DC machine, the armature MMF signal shape is?SinusoidalTriangularSquarePulsatingHintIt is a non-sinusoidal waveform 55). Which of the following is used to get sparkles communication?WindingInter polesBrushesEyeboltHintIt is used to overcome the self-induction effect for the DC machine 56). When does a series generator excite?When load current is not equal to zeroWhen load current is zeroOnce the supply is providedOnce the speed is increasedHintOnce the maximum current is not equivalent to zero 57). Once the field winding resistance in a DC generator is increased then the o/p voltage will be….?DecreasedDecreasedZeroNone of the aboveHintHere, the output voltage is opposite to the resistance 58). When the generator runs on no-load then which of the following type generator will have negligible terminal voltage?Shunt generatorSeries generatorSeparately excitedPermanent magnetHintIn this generator, the two winding's are connected in series 59). The armature MMF in a DC machine is directed through the…axis?PolarInterpolarBrushNone of the aboveHintIt is directed on the brush axis 60). The armature winding in DC machines is located on the rotor for…?Voltage generationCommunicationGeneration of voltageControlling the motor speedHintFor interaction purposes, it is located. 61). A machine that is used to change the energy from mechanical to electrical is called?GeneratorMotorTransformerBatteryHintMotors and generators are called machines 62). Which generator provides stable voltage for different loads?Level compoundedSeriesPermanent magnetShunt generatorsHintIn this generator, the terminal voltage is the same at a fixed current 63). The reciprocal of reluctance is known as?ResistanceSeriesInductancePermeanceHintThis coefficient is used to design the magnetic circuit 64). Which of the following brush has less voltage drop?CarbonYoke pole armatureGraphiteMetal graphiteHintThese brushes includes a brush body 65). Which of the following component is used to provide DC for a DC generator?CommutatorEyeboltWindingsRotorHintIt is a rotary electrical switch 66). The brushes within a commutator mainly depend on…?CommutatorWindingsEyeboltBased on controlling currentHintThe amount of controlling of current 67). How the magnetic field can be generated within DC machines?CommutatorElectromagnetsEyeboltWindingsHintThese are made with wire coils 68). In commutator segments, the insulating material used is…?PaperGraphiteMicaDielectricHintThis material is a group of minerals 69). Which of the following material is used to make brushes?CopperCarbonAluminumIronHintThese materials have different structures as well as properties 70). The field coils are made with?CopperMicaAluminumCarbonHintThe chemical element of this material is Cu 71). What is the name of the first electrical generator?ThomsonAntonioDynamoFaradayHintThese generators produce pulsing DC using a commutator 72). The name of the first electromagnetic generator is…?Faraqday DiscDynamoAntonioFaradayHintIt is a homopolar generator 73). The electromagnetic generator was invented in which year…?1820183518311905HintIt was invented by Michael faraday 74). The function of an electric generator is quite opposite of…?Electric MotorTurbineTransformerFusesHintIt converts the energy from electrical to mechanical 75). How many categories are there in electromagnetic generators?2345HintThey are alternators and dynamosDC Generator MCQs for Quiz 76). In a DC machine, the external frame is called as?RotorStatorYokeCommutatorHintIt is a stationary part in dc machines 77). How many principal components are there in DC machines?2356HintSome of them are yoke, commutator, brushes, etc. 78). How the poles are connected to the yoke in DC machines?Using Welding or BoltsUsing WindingsUsing WiresUsing MagnetsHintThe connection of poles can be done using the welding process 79). The field system in DC generators is used to generate?Electromagnetic fieldUniform magnetic fieldElectric fieldMagnetic & Electric FieldsHintThis has a similar magnitude & direction 80). Practical DC machines include….?Air gapsEyeboltsWindingsCommutatorsHintThese ranges from 0.5 mm - 1.5 mm Please refer to this link to know more about DC Machine 81). Which of the following device is used to convert AC to DC and DC to AC?CommutatorEyeboltsWindingsBrushesHint: It is a mechanical rectifier 82). How many types of losses are there in the DC machine?2345HintThey are copper, iron & mechanical Please refer to this link to know more about Types of Losses in DC Machine 83). The principle used by the generator to convert the energy is?E.M.FMagnetic InductionFlemming’s left-hand ruleUniform magnetic fieldHintThis was discovered by Michael Faraday 84). In a generator, when the power loss occurs within the armature winding then it is known as?Copper lossEddy current lossMechanical lossHysteresis lossHintIt is an I2R loss 85). A heat loss is called as?Copper lossHysteresis lossMechanical lossEddy current lossHintThis loss mainly occurs because of the armature’s magnetic properties 86). Which of the following construction is the main difference between practical and normal generators?ArmatureBrushesYokeStatorHintIn a DC machine, it is a winding 87). In the series-wound type, which of the following are connected with the armature in series?.Field windingsBrushesLoadStatorHintIt is an electromagnet 88). In a shunt-wound generator, the field coils are connected in shunt with…?.LoadField windingsStatorRotorHintAn object which is lifted or moved. 89). Which of the following occurs when the load changes in a generator?Voltage regulationVoltage controlCurrent controlCurrent regulationHintIt is an internal action 90). Which of the following is used for increasing/reducing terminal voltage?Current controlVoltage regulationVoltage controlCurrent regulationHintIt is an imposed action 91). When the generators are connected in parallel then they provide?More currentMore voltageMore powerMore resistanceHintIt provides huge electrical energy 92). The special-purpose type DC generators are called as?MetadyneAmplidyneAlternatorRheostatHintThese are dc machines, used for generating huge DC 93). Armature types in DC generator are?2345HintThey are Gramme ring & drum type 94). Once the voltage is provided to the main windings then it is known as?Self ExcitationField ExcitationExcitationVoltage regulationHintIt decides the direction and strength of the magnetic field 95). The generator which gets current from an external source?Series woundSeparately excitedSelf-excitedShunt-woundHintThe coil is energized by an external source 96). Which of the following generator uses their o/p voltage to strengthen field coils?Self-excitedSeries woundShunt-woundSeparately excitedHintThey generate EMF 97). The output changes with load currents directly in….generators?Self-excitedShunt-woundSeparately excitedSeries woundHintIn this generator, the field coils with armature winding is connected in series 98). The distribution of actual flux in dc generators mainly depends on…?Air gap sizeWindingsYokeRotorHintIt depends on the size of an air gap 99). Which of the following material is harder in a commutator?MicaCopperSiliconSilverHintIt is stronger than copper 100). The voltage build-up in a shunt generator can be restricted by?Heat generatedLimitation of speedInsulationIron SaturationHintIt is measured like a percentage Time is Up! Time's up
