輪機(jī)專業(yè)英語(yǔ)3

2885.isnotinstalledontheemergencyswitchboard.A.ControlpanelB.ParallelingpanelC.LoadpanelD.Busbar注：應(yīng)急電源不需并聯(lián)操作，故選B2886.2886.isnotinstalledontheemergencyswitchboard.A.AmmeterandchangeoverswitchB.SpeedgovernordeviceC.SynchroscopeD.Wattmeter注：應(yīng)急電源不需并聯(lián)操作，不需同步表，故選C。Synchroscope同步表2887.belongstoemergencypowersupplyingequipments.A.NavigationlampB.WindlassC.MainseawaterpumpD.Compressor注：航行燈要由應(yīng)急電源供電，故選A2888.2888.belongstoemergencypowersupplyingequipments.A.AccommodationlightingB.WindlassC.MainseawaterpumpD.Compressor注：生活區(qū)照明燈要由應(yīng)急電源供電，故選A2889.belongstoemergencypowersupplyingequipments.A.EmergencyfirepumpB.WindlassC.MainseawaterpumpD.Freshwaterpump注：應(yīng)急消防泵為應(yīng)急供電設(shè)備之一，故選A2890.2890.belongstoemergencypowersupplyingequipments.A.CargowinchB.WindlassC.SteeringgearD.Aircompressor注：舵機(jī)為應(yīng)急供電設(shè)備之一，故選c2891.isnotinstalledontheemergencyswitchboard.A.AmmeterB.VoltmeterC.WattmeterD.Synchroscope

注：應(yīng)急配電板上沒(méi)有同步表，故選D2892.2892.Emergencygeneratorisinstalledonboardmainlyto.A.connecttothebusbarwhentheloadincreasingB.supplypowerspeciallytochargingpanelC.beputintooperationduringtheshiparrivingatorleavingportD.ensurethepowersupplytocriticalequipmentafterthemainswitchboardoutofpower注：船上的應(yīng)急發(fā)電機(jī)主要是確保在主配電板失電后向重要的設(shè)備供電，故選D2893.Afterresolvingthetroubleofmainpowersupply,mainswitchofemergencygeneratorshould，ifpowersupplyisrefreshed.A.beswitchedoffbythedutyofficerB.beswitchedonbythedutyofficerC.beswitchedoffautomaticallyD.beswitchedonautomatically注：主電源恢復(fù)后，應(yīng)急發(fā)電機(jī)應(yīng)自動(dòng)切斷，故選c2894.2894.aresuppliedbymainswitchboarddirectly.A.SuezCanalsearchlight,aircompressorandairconditioningcompressorB.Aircompressor,boilerblowerandrefrigerationplantC.Boilerblower,SuezCanalsearchlightandrefrigerationplantD.Suezcanalsearchlight,aircompressorandboilerblower注：蘇伊士運(yùn)河燈、空壓機(jī)、鍋爐鼓風(fēng)機(jī)由主配電板直接供電，故選D2895.isnotapartofthemainswitchboard.A.ControlpanelofmaingeneratorB.ControlpanelofemergencygeneratorC.ParallelingpanelD.Loadpanelofmaingenerator注：應(yīng)急發(fā)電機(jī)控制板不屬于主配電板，選B2896.2896.isnotapartofthemainswitchboard.A.BusbarB.LoadpanelofmaingeneratorC.ParallelingpanelD.Shoreconnectionbox注：岸電箱不屬于主配電板，選D2897.isusedtocontrol，modulate，monitorandprotectgeneratorset.A.ControlpanelB.LoadpanelC.ParallelingpanelD.Busbar

注：控制板用于控制、調(diào)節(jié)、監(jiān)視和保護(hù)發(fā)電機(jī)組，故選A2898.2898.一isnotinstalledonthemainswitchboard.A.AmmeterandchangeoverswitchB.PowerfactormeterC.SynchroscopeD.Reversesequencerelay注：主配電板上沒(méi)有D項(xiàng)所指的部件，故選D2899.To，thepowerissuppliedbymainswitchboarddirectlynotthoughsub-board.A.savenetworkcostB.improvethereliabilityofsupplyingpowertoimportantloadC.preventsequencereverseD.increasethepowerfactorofimportantload注：主配電板直接向重要負(fù)載供電，以提高可靠性，故選B2900.2900.Synchrocopeandsynchrolightarelocatedonofmainswitchboard.A.loadpanelB.emergencygeneratorcontrolpanel

C.batterycharginganddischargingpanelD.parallelingpanel注：同步表和同步指示燈裝在并車屏上，故選D2901.Insulationlightislocatedonofmainswitchboard.A.parallelingpanelB.loadpanelC.emergencygeneratorcontrolpaneD.maingeneratorcontrolpane注：絕緣燈裝在負(fù)載屏上，故選B2902.2902.arelocatedontheloadpanelofmainswitchboard.A.Megohmmeter,insulationlightandsynchroscopeB.Synchroscope

，synchrolightandmegohmmeterC.Shorepowerswitch,insulationlightandsynchroscopeD.Megohmmeter,insulationlightandshorepowerswitch注：兆歐表、絕緣燈和岸電開(kāi)關(guān)裝在負(fù)載屛上，故選D。Megohm

rnete^S歐表2903.ispowersuppliedbymainswitchboarddirectlynotthroughsub-board.A.DeckmachineryB.LittlepowerloadC.SomeimportantloadD.stationarysubmersiblepump注：重要負(fù)載直接由主配電板供電，故選c2904.2904.is(are)notpowersuppliedbymainswitchboarddirectly.A.SteeringgearandwindlassB.NavigationlightandradiopowerpanelC.NavigationdevicepowerboxD.Dailyfreshwaterpump注：日用淡水泵不由主配電板直接供電，故選DLesson30MarineElectricEquipment(船用電氣系統(tǒng))2905.Thestar-deltastarterisaneffectivemethodofvoltagestartingofamotor.A.increasedB.reducedC.unchangedD.noneoftheabove注：Y-A啟動(dòng)器能使電機(jī)降壓?jiǎn)?dòng)，故選B2906.2906.Priortoanyoverhaulworkonelectricequipment,itisimportanttoensurethecircuitsareA.liveB.deadC.excitedD.online注：電氣設(shè)備維修之前，最重要的是確保其不帶電，故選B2907.MoistureinaD.C.motorwouldcause.A.shortcircuitB.speedupC.slowdownD.hunting注：moisture潮濕，直流電動(dòng)機(jī)潮濕會(huì)引起短路，故選A2908.2908.Electricinsulationismadeoforganicsubstancesandsograduallywithage.A.deterioratesB.increasesC.arefouledD.becomesbetter注：題意為由有機(jī)物構(gòu)成的絕緣材料會(huì)隨時(shí)間的推移而逐漸變差，故選A。organicsub--stance有機(jī)物，deteriorate退化、變壞2909.shallbecontinuouslypoweredandshallhaveanautomaticchangeovertoastandbypowersupplyincaseoflossofnormalpowersupply.A.CoolingsystemB.AlarmsystemC.TheairconditioninginstallationD.Themooringequipment注：coolingsystem冷卻系統(tǒng)，alarmsystem報(bào)警系統(tǒng)，airconditioninginstallation空調(diào)裝置，mooringequipment系泊設(shè)備，這些系統(tǒng)（設(shè)備）當(dāng)中，須不間斷供電的只有報(bào)警系統(tǒng)，故選B2910.AgroundcanbedefinedasanelectricalconnectionbetweenthewiringofamotoranditsA.shuntfieldB.circuitbreakerC.metalframeworkD.inter-pole注：groimd接地，metalframework金屬框架，電動(dòng)機(jī)接地即為電路某處與金屬框架的電氣連接，故選c2911.2911.Anyelectricmotorcanbeconstructedtobe.A.shortproofB.groundproofC.explosionproofD.overloadproof注：explosionproof防爆的，顯然，電動(dòng)機(jī)可做成防爆的，故選C2912.Whichofthefollowingstatementsrepresentsthemaindifferencebetweenarelayandacon-tactor?A.Contactorscontrolcurrentandrelayscontrolvoltage.B.Arelayisseriesconnectedandacontactorisparallelconnected.C.Contactorscanhandleheavierloadsthanrelays.D.Contactorsaremadefromsilverandrelaysaremadefromcopper.注：繼電器與接觸器的區(qū)別在于容量不同，前者小后者大，故選C。represent描述，relay繼電器，contactor接觸器。3913.Anaccidentalpathoflowresistance,allowingpassageofabnormalamountofcurrentisknownasa/an.A.opencircuitB.shortcircuitC.polarizedgroundD.groundreferencepoint注：電流通路意外低阻，異常電流通過(guò)，此為短路（shortcircuit)現(xiàn)象，故選B。A為開(kāi)路，C為極化地，D為接地參考點(diǎn)2914.2914.Aresistanceinacircuitofunknownvalueistobetestedusingthevoltmeter/ammetermethod.Therefore，themetersshouldbeconnectedwith.A.bothmetersinserieswiththeresistanceB.bothmetersinparallelwiththeresistanceC.theammeterinseriesandthevoltmeterinparallelwiththeresistanceD.theammeterinparallelandthevoltmeterinserieswiththeresistance注：用伏安法測(cè)量電阻的阻值時(shí)，電流表與待測(cè)電阻串聯(lián)而電壓表與待測(cè)電阻并聯(lián)，故選C2915.Whichofthefollowingelectricmotorswouldbethesafestandmostreliabletouseonthemaindeckofavesselinfoulweatherconditions?A.Sealedmotors.B.Dripproofmotors.C.Enclosedmotors.D.Watertightmotors.注：sealed密封的，dripproof防滴漏的，enclosed封閉的，watertight水密的，這幾個(gè)詞意思相近，但watertight更準(zhǔn)確，故選D2916.2916.Whichofthelisteddevicesisusedtomeasurepressureandconvertittoanelectricalsignal?A.Transducer.B.Reducer.C,Transformer.D.Rectifier.注：將壓力轉(zhuǎn)變?yōu)殡娦盘?hào)的是傳感器，故選A。Transducer傳感器，reducer節(jié)流器，transformer變壓器，rectifier校正器2917.ThedevicethatmostcommonlyutilizestheprincipleofelectromagneticinductionistheA.diodeB.transformerC.transistorD.rheostat注：diode二極管，transformer變壓器，transistor晶體管，rheostat變阻器，顯然，利用電磁感應(yīng)原理工作的只有變壓器，故選B2918.2918.Whichofthemotorsforthedeviceslistedbelowisfittedwithaninstantaneousoverloadrelay?A.Fan.B.Pump.C.Winch.D.Machinetool.注：instantaneousoverloadrelay瞬時(shí)過(guò)載繼電器，絞車（winch)-般需要裝配此保護(hù)裝置，故選c2919.TheWheat-stonebridgeisaprecisionmeasuringinstrumentutilizingtheprincipleofchan-gesin.A.inductance.B.capacitance.C.resistance.D.amperage.注：Wheat-stonebridge惠斯通電橋，惠斯通電橋是利用電阻變化原理來(lái)工作的精確測(cè)量?jī)x表，inductance電感，capacitance電容，resistance電阻，amperage電流,根據(jù)題意，故選C2920.2920.Thegreatestdetrimentaleffectonidleelectricalequipment,suchascargopumpmotors,istheA.lossofresidualmagnetismB.absorptionofmoistureintheinsulationC.insulationvarnishflakingD.dirtcollectingonthewindings注：對(duì)如貨油泵馬達(dá)等閑置電氣設(shè)備最大的危害是絕緣吸潮。A為磁損失，B為絕緣吸潮，C為絕緣漆剝落，D為繞組集污，故選B2921.Anelectricaldevicewhichpreventsanactionfromoccurringuntilallotherrequiredcondi-tionsaremetiscalleda/an.A.limitB.monitorC.modulatorD.interlock注：limit極限，monitor監(jiān)視器，modulator調(diào)制器，interlock聯(lián)鎖，顯然，防止在其它條件未滿足之前發(fā)生動(dòng)作的電氣裝置是聯(lián)鎖裝置，故選D2922.2922.Acircuitbreakerandafusehaveabasicsimilarityinthattheyboth___.A.canberesettoenergizethecircuitB.shouldopenthecircuitwhenoverloadedC.willbumoutwhenanovercurrentflowdevelopsD.alloftheabove注：斷路器及保險(xiǎn)絲的共同點(diǎn)在于過(guò)載時(shí)使電路開(kāi)路，故選B2923.Theelectrolyteinalead-acidstoragebatteryconsistsofdistilledwaterand.A.hydrogenchlorideB.calciumchlorideC.sulfuricacidD.muriaticacid注：在鉛-酸蓄電池中，電解質(zhì)由蒸餾水和...構(gòu)成。electrolyte電解質(zhì)，lead-acidstoragebattery鉛-酸蓄電池，A為氯化氫，B為氯化鈣，C為硫酸，D為鹽酸，故選C2924.2924.Electricalleadsandinsulationonamotorshouldbepaintedwith.A.heat-resistingacrylicB.heat-resistingaluminumC,insulatingvarnishD.insulatingwhitelead注：電動(dòng)機(jī)上的連接線和絕緣體應(yīng)涂上絕緣漆。A為耐熱纖維，B為耐熱鋁，C為絕緣漆，D為絕緣漆，故選C2925.Acircuitbreakerdiffersfromafuseinthatacircuitbreaker.A.meltsandmustbereplacedB.isenclosedinatubeofinsulatingmaterialwithmetalferrulesateachendC.givesnovisualindicationofhavingopenedthecircuitD.tripstobreakthecircuitandmaybereset注：斷路器不同于保險(xiǎn)絲在于其能夠跳開(kāi)電路并可以復(fù)位，而保險(xiǎn)絲熔斷后只能換新，故選D2926.2926.Asageneralrule，thefirsttroubleshootingactiontobetakenincheckingfaultyelectriccontroldevicesisto.A.drawaonelinediagramofthecircuitryBtestallfusesandmeasurethelinevoltageC.takemeggerreadingsD.insulatetheapparatusfromground注：對(duì)電氣控制設(shè)備進(jìn)行故障排查時(shí)，通常做法是首先測(cè)試保險(xiǎn)絲和測(cè)量電壓，故選B2927.Anelectricaldevicewhichemploysastationaryarmatureandarotatingelectromagneticfieldisusedaboardshipasa.A.magneticamplifierB.ship'sservicealternatorC.three-wireDCgeneratorD.saturablecorereactor注：船上，采用靜止電樞及旋轉(zhuǎn)電磁場(chǎng)的電氣設(shè)備顯然是船用交流發(fā)電機(jī)，故選B2928.2928.Thefirstrequirementforlogicaltroubleshootingofanysystemistheabilityto.A.collectallavailabledataonacasualtyB.recognizenormaloperation

C.identifytheprobablecauseofasymptomD.isolatethefaultycomponent注：任何系統(tǒng)的故障排查的首要要求是能夠辯認(rèn)正常運(yùn)行。A為收集故障的所有有用數(shù)據(jù)，B為辨認(rèn)正常運(yùn)行，C為識(shí)別故障征兆的可能原因，D為隔離故障部件，故選B2929.Afusethatblowsoftenshouldbereplacedonlywithafuseof.A.therecommendedcurrentandvoltageratingB.highercurrentandvoltageratingC.highercurrentandlowervoltageratingD.lowercurrentandhighervoltagerating注：保險(xiǎn)絲熔斷后，應(yīng)用推薦的額定電流與電壓的保險(xiǎn)絲換新，不能用更高或更低額定值的保險(xiǎn)絲來(lái)更換，故選A。recommended推薦的，指定的2930.2930.Torepairasmallelectricalmotorthathasbeensubmergedinsaltwater,youshould.A.washitwithfreshwaterandapplyanexternalsourceofheatB.renewthewindingsC.senditashoretoanapprovedservicefacilityD.rinseallelectricalpartswithacarbontetrachloridecleaningsolventandthenblowdrythemotorwithcompressedair注：對(duì)被海水浸泡的小型電動(dòng)機(jī)的維修，一般做法是用清水清洗并烘干，故選A。B為換新繞組，C為送岸上認(rèn)證機(jī)構(gòu)處理，D為用四氯化碳清洗液清洗并吹干2931.Thefunctionofdamperwindingsinasynchronousmotoristo,A.eliminateslippageB.provideexcitationC.providestartingtorqueD.increaseefficiency注：同步電動(dòng)機(jī)的阻尼繞組（damperwindings)的作用是提供起動(dòng)扭矩，故選C。A為消除滑移，B為提供勵(lì)磁，D為提高效率，均不正確2932.2932.Timedelayedordelayedaction-typefusesaredesignedto,A.preventgroundsinbranchcircuitsB.preventopensinmotorcircuitsC.permitmomentaryoverloadswithoutmeltingD.guardlightingandelectroniccircuits注：延時(shí)動(dòng)作式保險(xiǎn)絲的主要作用就是允許被保護(hù)電路瞬時(shí)過(guò)載而不熔斷，故選C。momentary瞬間的2933.Thepartofafusethatmeltsandopensthecircuitismadeof*A.copperandantimonyB.steelandbabbittC.aluminumorberylliumalloyD.zincoranalloyoftinandlead注：保險(xiǎn)絲由什么材料成；A為銅和銻，B為鋼和巴氏合金，C為鋁或鈹合金，D為鋅或錫鉛合金，故選D2934.2934.Themaindifferencebetweenamotorcontrolcircuitcontaininglowvoltageprotectionandlowvoltagereleaseisthatthelattercontains?A.amagneticoperatingcoilB.normallyopenlinecontactsC.thermal-overloadprotectionD.amomentary-contactstartbutton注：帶低壓保護(hù)的電機(jī)控制電路與帶低壓釋放的電機(jī)控制電路的主要區(qū)別在于后者帶有瞬時(shí)接觸起動(dòng)按鈕。A為磁動(dòng)線圈，B為常開(kāi)觸頭，C為過(guò)熱保護(hù)，D為瞬時(shí)接觸起動(dòng)按鈕。故選D2935.Fusesplacedinserieswithathermaltrip-typecircuitbreakerareusedfor.A.time-delayprotectionB.short-circuitprotectionC.shortdurationsurgeprotectionD.sustainedoverloadprotection注：thermaltrip-typecircuitbreaker熱斷路器（即雙金屬片開(kāi)關(guān)），在其電路中串聯(lián)保險(xiǎn)絲用作短路保護(hù)，故選B。A為延時(shí)保護(hù)，C為短期峰壓保護(hù)，D為持續(xù)過(guò)載保護(hù)，均不正確2936.2936.AmmetersandvoltmetersusedinsinusoidalA.C.powersystemsindicatewhichofthefol-lowingvaluesofthewaveformsmeasured?A.Peakvalue.B.Root-mean-squarevalue.C.Averagevalue.D.Maximumvalue.注：sirmsoickl正弦的，在正弦交流電力系統(tǒng)中，電流表和電壓表指示的是有效值，即均方根值，故選B。A為峰值，C為平均值，D為最大值，均與實(shí)際情況不符2937.Sincefuseelementsaremadeofzincoranyalloyoftinandlead，themeltingpointofthefuseelementmustbe.A.higherthanthatofcopperB.lowerthanthatofcopperC.equaltothatofcopperD.reachedwhentheconductoritisprotectingbecomes"whitehot"注：保險(xiǎn)絲由鋅或錫鉛合金做成，其熔點(diǎn)要比銅的熔點(diǎn)低，故選B。D為當(dāng)其所保護(hù)的導(dǎo)線達(dá)到白熱化時(shí)其溫度升至熔點(diǎn)溫度，不準(zhǔn)確2938.2938.Whichofthelistedprecautionsshouldbetakenwhencleaningtheinternalsofamotorwithcompressedair?A.Openthemachineonbothendssoastoallowtheairanddusttoescape.B.Becertainthatthecircuitbreakerisopenedandtaggedonthefeederpanel.C.Becertainthattheairiscleanandasdryaspossible.D.Alloftheabove.注：用壓縮空氣吹洗電機(jī)內(nèi)部時(shí)，要采取下列哪些保護(hù)措施??A為電機(jī)兩端打開(kāi)以便空氣進(jìn)人及污物的吹走；B為確保電路斷開(kāi)并在配電板上懸掛作業(yè)標(biāo)志；C為確?？諝獗M可能清潔和干燥；這些都是要采取的保護(hù)措施，故選D2939.Powertransformersareratedin.A.kilowattsB.ampere-turnsC.kilowatt-voltsD.kilovolt-amperes：kilowatt千瓦，ampere-turn安培-匝數(shù)kilowatt-volt千瓦伏，kilovolt-ampere千伏安;根據(jù)題意，變壓器的標(biāo)定是以千伏安的單位的，故選D2940.2940.Adevicewhichprintsoutapermanentrecordoftheplantoperatingconditionsisknownasthe.A.analoggerB.bellloggerC.alarmloggerD.datalogger注：打印機(jī)器運(yùn)行工況持久記錄的裝置稱為數(shù)據(jù)記錄儀。analogger語(yǔ)錄；belllogger傳令鐘記錄儀；alarmlogger報(bào)警記錄儀；datalogger數(shù)據(jù)記錄儀，故選D2941.Copperisoftenusedasanelectricalconductorbecauseit.A.hashighresistanceatlowtemperaturesB.hasahighlypolishedsurfaceC.isabletopasscurrentwithlittleoppositionD.holdsinsulationtogetherwell注：銅常被用作電線是因?yàn)橥ㄟ^(guò)的電流阻礙小。A為具有低溫高阻特性；B為具有高度磨光的表面；C為對(duì)通過(guò)的電流阻礙小；D為能很好地與絕緣材料在一起，故選C2942.2942.Routinemaintenanceofleadacidbatteriesshouldinclude?A.keepingtheterminalscleanB.coatingcableconnectionswithpetroleumjellyC.maintainingatricklechargeD.alloftheabove注：題意為對(duì)鉛酸蓄電池的日常維護(hù)包括保持接線端清潔；電纜接頭涂上凡士林；保持連續(xù)充電；顯然這些均為日常保養(yǎng)工作，故選D2943.Electricalcircuitsareprotectedagainstoverheatingbymeansofa/an.A.circuitbreakerB.amplifierC.diodeD.capacitor注：題意為：電路是通過(guò)繼路器來(lái)防止過(guò)熱的。只有circuitbreaker斷路器有此功能，故選入。amplifier放大器；diode二極管；capacitor電容器2944.2944.Thefunctionofarectifierissimilartothatofa.A.trapB.regulatingvalveC.checkvalveD.filter注：rectifier整流器，整流器的功能與止回閥相類似。Trap捕集器；regulatingvalve調(diào)節(jié)閥；checkvalve止回閥；filter過(guò)濾器。根據(jù)題意，故選C2945.Mostconductingmaterialssuchascopper,aluminum,iron,nickel,andtungsten.A.increaseinresistancewithincreasedtemperature.B.increaseinresistancewithdecreasedtemperature.C.decreaseinresistancewithincreasedtemperature.D.increaseinconductancewithincreasedtemperature.注：大多數(shù)導(dǎo)電材料具有正的溫度系數(shù)，即其電阻值會(huì)隨溫度的升高而增加，故選A2946.2946.Inaseriescircuit,whichvaluewillremainunchangedatallplacesinthecircuit?A.Voltage.B.CurrentC.Resistance.D.Inductance.注：串聯(lián)電路中，任何位置的電流都是相等的，故選B2947.Reducedvoltageappliedtoamotorduringthestartingperiodwill,A.resultindecreasedaccelerationtimeonlyB.lowerthestartingcurrentandincreaseacceleratingtimeC.causeagreaterstartingtorqueD.increasethestartingcurrentandpumpcapacity注：電機(jī)起動(dòng)時(shí)降低電壓，則會(huì)降低起動(dòng)電流和增加加速時(shí)間。A為僅導(dǎo)致加速時(shí)間縮短；B為降低起動(dòng)電流和增加加速時(shí)間；C為產(chǎn)生更大的起動(dòng)轉(zhuǎn)矩；D為提高起動(dòng)電流及泵的排量，故選B2948.2948.Whenyouaremakingahighpotentialtestonapieceofrepairedelectricalmachinery，ariseinleakagecurrentindicates.A.goodinsulationB.badinsulationC.highinsulationpowerfactorD.ahighslotdischargefactor注：highpotentialtest耐壓試驗(yàn)，對(duì)已維修的電器設(shè)備進(jìn)行耐壓試驗(yàn)時(shí)，漏電流的升高意味著絕緣變差。A為絕緣良好；B為絕緣變差；C為絕緣功率因數(shù)高；D為高放電系數(shù)。根據(jù)題意，故選B2949.Thetotalresistanceofaparallelcircuitisalways-A.largerthanthegreatestbranchresistanceB.smallerthanthelowestbranchresistanceC.equaltothesumoftheindividualbranchresistancesD.one-halfthesumoftheindividualbranchresistances注：并聯(lián)電路和總電阻總是比各分支電路的最小電阻還要小，故選B2950.2950.Asemiconductorisamaterialwitha.A.conductivityhigherthananormalconductorB.conductivityhigherthananormalinsulatorC.highconductivityatlowtemperaturesD.lowconductivityathightemperatures注：semiconductor半導(dǎo)體，conductivity導(dǎo)電性能；半導(dǎo)體的導(dǎo)電性能介于導(dǎo)體和絕緣體之間；故選B2951.Theresistanceofaconductorvaries.A.directlyasitslengthandinverselyasitscross-sectionalareaB.inverselyasitslengthanddirectlyasitscross-sectionalareaC.directlyasitslengthanddirectlyasitscross-sectionalareaD.inverselyasitslengthandinverselyasitscross-sectionalarea注：directly正比，inversely反比，cross-sectionalarea橫截面積；電導(dǎo)體的電阻值正比于其長(zhǎng)度而反比于其橫截面積，故選A2952.2952.Aboardship,agroundedfieldcoilinanac.motorcanbedeterminedbyusinga.A.portablegrowlerB.galvanometerC.visualinspectionD.megohmmeter

注：在船上，交流電機(jī)的勵(lì)磁線圈對(duì)地短接可通過(guò)兆歐表來(lái)判斷。portablegrowler便攜式短路線圈測(cè)試儀；galvanometer靈敏電流計(jì)；visualinspection目測(cè)檢査；megohmmeter

兆歐表；實(shí)際當(dāng)中，一般用兆歐表測(cè)量線圈與地間的絕緣電阻的大小來(lái)判斷是否對(duì)地短路，故選D2953.Greasecoatingsonelectricalcontactsurfacesincreasecontactresistanceandshouldbere-movedwitha?A.smallwirebrushB.compressedairjetC.cleandryclothD.10%solutioncarbonsolventandwater注：電氣接觸面的油膜會(huì)增加接觸電阻，應(yīng)用干燥清潔的布.來(lái)清除。A為小鋼絲刷；B為壓縮空氣噴嘴；C為干燥清潔的布；D為10%的碳溶液和水；實(shí)際中應(yīng)用干燥清潔的布來(lái)清潔，故選c2954.2954.Agroundinanelectricalcircuitoutsidetheengineroom.A.cannotbedetectedundernormalconditionsB.isofnoconsequencetoengineeringpersonnelC.isindicatedatthebranchcircuitbreakerpanelD.isindicatedbythegrounddetectinglampsonthemainswitchboard注：主配電板中一般有一個(gè)接地故障指示燈，用以指示接地故障，故選D2955.Whichofthefollowingstatementsconcerningasimpleparallelresistancecircuitiscorrect?A.Thevoltagedropacrosseachresistoristhesame.B.Thetotalcurrentflowequalsthereciprocalofthesumoftheindividualcurrents.C.Thetotalresistanceequalsthesumoftheindividualresistances.D.Thetotalvoltageequalsthesumoftheindividualvoltagesacrosseachresistance.注：有關(guān)純電阻并聯(lián)電路，正確的說(shuō)法是各電阻兩端的電壓降相等。B為總電流等于各分支電流總和的倒數(shù)；C為總電阻等于各分支電阻之和；D為總電壓等于各分支電阻電壓之和，故選A。reciprocal倒數(shù)2956.2956.Whichofthelisteditemswillstopamotorduetoareductioninvoltageandrestartitwhenthevoltageisrestoredtonormal?A.Lowvoltageprotectioncircuit.B.Non-renewablelinkfuse.C.Renewablelinkfuse.D.Lowvoltagereleasecircuit.注：低壓釋放電路會(huì)因電壓降低而停止電機(jī)并在電壓恢復(fù)正常時(shí)重新啟動(dòng)電機(jī)。A為低壓保護(hù)電路；B為一次性保險(xiǎn)絲；C為可換新保險(xiǎn)絲；D為低壓釋放電路；實(shí)際上，低壓釋放電路實(shí)現(xiàn)此功能，故選D2957.Whichofthefollowingstatementsistrueconcerningsimpleparallelresistancecircuits?A.Thetotalcurrentflowequalsthesumoftheindividualcurrents.B.Thetotalcurrentflowequalsthereciprocalofthesumoftheindividualcurrents.C.Thetotalresistanceequalsthesumoftheindividualresistance.D.Thetotalvoltageequalsthesumoftheindividualvoltagesacrosseachresistance.注：純電阻并聯(lián)電路為總電流等于各分支電流之和。B為總電流等于各分支電流總和的倒數(shù)；C為總電阻等于各分支電阻之和；D為總電壓等于各分支電阻電壓之和，故選人2958.2958.Anohmmetercanbeusedtomeasure.A.currentflowinacircuitB.voltagebetweentwopointsinacircuitC.circuitcontinuityD.power注：circuitcontinuity電路的導(dǎo)通情況；歐姆表既不能測(cè)電流，不能測(cè)電壓，也不能測(cè)功率，而可檢測(cè)電路的接通情況，故選C2959.Whenplacedinamagneticfield，whichofthematerialslistedwillmaintainthehighestpermeability?A.GlassB.BakeliteC.SoftironD.Aluminum注：permeability導(dǎo)磁率；glass玻璃；bakelite膠木；softiron軟鐵；aluminum鋁；這些材料中，除軟鐵外，均為不導(dǎo)磁的材料，故選c2960.2960.Atransformerinanelectriccircuitservesto.A.generateitsownelectricalpowerB.transformelectricalenergyintomechanicalenergyC.increaseordecreasecircuitvoltageasrequiredD.convertACcurrenttoDCcurrent注：變壓器在電路中的作用是根據(jù)需要升高或降低電壓，故選c2961.Themainpurposeofanelectricspaceheaterinstalledinalargea.c.generatoristo.A.preventthewindingsfrombecomingbrittleB.preventmoisturefromcondensinginthewindingsduringshutdownC.preventacidicpittingoftheslipringsD.keepthelubeoilwarmforquickstarting注：spaceheater空氣加熱器，大型交流發(fā)電機(jī)裝有電加熱器的主要目的是防止停車時(shí)水氣在繞組上結(jié)露。A為防止繞組變得易碎；B為防止停車時(shí)水氣在繞組上結(jié)露；C為防止滑環(huán)的酸性腐蝕；D為保持滑油溫度以便快速啟動(dòng)，故選B2962.2962.PriortostartinganA.C.generatorprimemover,thevoltageregulatorcutoutswitchshouldbeplacedinthe.A.manualpositionB.busneutralpositionC.raisevoltagepositionD.transferposition注：起動(dòng)交流發(fā)電機(jī)的原動(dòng)機(jī)之前，電壓調(diào)節(jié)器切斷開(kāi)關(guān)應(yīng)置于手動(dòng)位置。B為匯流排中間位置；C為升壓位置；D為轉(zhuǎn)換位置；實(shí)際當(dāng)中，應(yīng)將其置于手動(dòng)位置，故選A2963.Whensecuringana.c.generator,youshouldFIRST.A.openthegeneratorcircuitbreakerB.switchthevoltageregulatorto"manual"C.decreasethefieldexcitationtominimumD.reducetheloadontheunit注：securing,secure的現(xiàn)在分詞形式，原意為固定的意思，在這里有停車操作的意思；發(fā)電機(jī)停車時(shí)，首先應(yīng)卸載，故選D2964.2964.Whenmeasuringa.c.currentflow，youmustalwaysconnectthemeter.A.inserieswiththepowersourceandloadB.inparallelwiththepowersourceandloadC.insuringcorrectpolarityD.usingthelowestrangepossibletopreventinstrumentdamage注：在測(cè)量交流電流時(shí)，總須將電流表與電源及負(fù)載串聯(lián)。B為與電源及負(fù)載并聯(lián)；C為確保極性正確；D為盡可能用最低量程以免損壞儀表，故選A2965.Theprimaryfunctionofanelectricmotoristo.A.developtorqueB.generatehighvoltagesC.produceamagneticfieldD.generatehighelectricalresistance注：電動(dòng)機(jī)的主要功能是產(chǎn)生扭矩。B為產(chǎn)生高電壓；C為產(chǎn)生磁場(chǎng)；D為產(chǎn)生髙電阻。B、D選項(xiàng)均不是電動(dòng)機(jī)的功能，故選A2966.2966.CurrentmeasuringinstrumentsmustalwaysbeconnectedinA.serieswithacircuitB.parallelwithacircuitG.series-parallelwithacircuitD.deltawiththeshunt注：電流測(cè)量?jī)x表總須如何連接，故選A。2967.Anammetershouldbeusedtomeasure.A.thevoltagebetweentwopointsinacircuitB.circuitcontinuityC.currentflowinacircuitD.totalorpartialcircuitresistance注：電流表當(dāng)然是用來(lái)測(cè)量電流量的，故選c2968.Theoperatorofelectricalmotorsshouldkeepaconstantcheckontheloadstheycarrybe-cause,A.lowloadsnecessitatefrequentinsulationcleaningB.exceedingnameplatevaluesshortensusefullifeC.energyiswastediffullloadingisnotutilizedD.powerfactorcorrectionmethodsareloaddependent注：電機(jī)操作員應(yīng)經(jīng)常檢查動(dòng)機(jī)所帶負(fù)載，這是因?yàn)樨?fù)載超過(guò)銘牌標(biāo)定值會(huì)縮短使用壽命。A為低負(fù)載需要頻繁清潔絕緣子；B為負(fù)載超過(guò)銘牌標(biāo)定值會(huì)縮短使用壽命；C為若沒(méi)有使用滿負(fù)荷會(huì)造成能源浪費(fèi)；D為功率因數(shù)的校正取決于負(fù)載量，故選B2969.2969.CompletemaintenanceofelectricalmotorsshouldincludeperiodicchecksformachineA.vibrationB.watertightintegrityC.speeddroopD.reactivepower注：電機(jī)的徹底保養(yǎng)應(yīng)包括對(duì)機(jī)器的振動(dòng)定期檢查。B為水密完好性；C為速度降；D為無(wú)功功率。B為水密電機(jī)的檢查項(xiàng)目，C、D為發(fā)電機(jī)的檢查項(xiàng)目，故選A2970.Theneedforinsulationcleaningmaybedeterminedby.A.visualinspectionfordirtaccumulationB.highmeggerreadingsC.lowoperatingtemperatureD.thetimeperiodsincethelastcleaning注：判斷絕緣子是否需要清潔的依據(jù)是目測(cè)積污情況。B為高兆歐表讀數(shù)；C為運(yùn)行溫度低；D為距上次清潔的時(shí)間長(zhǎng)短，故選A2971.2971.Ambienttemperatureisthe,A.amountoftemperaturerisewithnoloadB.temperatureofthecompartmentwherethemotorislocatedC.normaloperatingtemperature，lesstheroomtemperatureD.amountoftemperaturedevelopedbyanoperatingmotor注：ambienttemperature環(huán)境溫度，指的是機(jī)器設(shè)備所處環(huán)境的溫度，故選B2972.Electriccircuitsareprotectedagainstoverloadsandshortcircuitsbymeansofa/an?A.circuitbreakerB.amplifierC.diodeD.capacitor注：電路的過(guò)載保護(hù)及短路保護(hù)是通過(guò)斷路器的實(shí)現(xiàn)的，故選A2973.2973.Moistureabsorbedinthewindingsorcondensedonthesurfaceofelectricalmachineryinsu

lation.A.isgoodforlongtermpreservingsincemostinsulationisorganicandcontainssomea-mountB.lowerstheinsulationvalueandisacommoncauseoffaultgroundsinidlemachinesC.willenhanceinsulationresistanceonlyifitisfreshwaterandcontainsnosaltD.reducestheamountofcurrentsuppliedordrawnbythemachinesohorsepowerislimited注：繞組潮濕或電氣設(shè)備絕緣子表面結(jié)露會(huì)導(dǎo)致絕緣電阻下降并常導(dǎo)致閑置機(jī)器接地故障，故選B2974.Toprotecttherotorofamotordisassembledformaintenanceoroverhaul,itshouldbeA.suspendedbywireslingsinonecomeroftheshopB.wrappedinseverallayersofheavypaperorcardboardC.supportedbyflatwoodblocksontheworkbenchD.returnedtotheframeassoonasthebearingsareremoved注：為了保護(hù)解體電機(jī)的轉(zhuǎn)子，應(yīng)該用n層報(bào)紙或者紙板包卷。A為用金屬繩懸掛于車間一角；B為用幾層硬紙或者紙板包裹；C為用平木塊支撐于工作臺(tái)上；D為拆下軸承后即裝回機(jī)架。實(shí)際上，B項(xiàng)做法能有效保護(hù)轉(zhuǎn)子，其它做法均會(huì)造成一定的損壞。故選B2975.2975.Whichofthefollowingmaterialsisagoodinsulator?A.Steel.B.Aluminum.C.Glass.D.Copper.注：steel鋼、aluminum鋁、copper銅均是導(dǎo)體，只有g(shù)lass玻璃是絕緣體，故選C2976.Ifasmallelectricmotorisimmersedinsaltwateritshouldbe.Iwashedinfreshwa-ter

IldriedinanovenA.IonlyB.IIonlyC.bothl

andllD.neither!orll

注：小型電機(jī)若被海水浸泡，則應(yīng)用清水清洗并烘干，故選C。oven爐子2977.2977.SomelargeA.Cmotorsareequippedwithheaters.Thesecouldbe.IresistanceheatersbolteddirectlytotheframeIIlowvoltagewindingsembeddedinthemotorwindingsA.IonlyB.IlonlyC.either!orllD.neither!orll

注：大型交流電機(jī)一般裝有加熱器，這可以將電阻式加熱器直接裝于機(jī)架上，也可以將低壓加熱繩圈嵌入到電機(jī)繞組當(dāng)中，故選C2978.IfaDCmotorrunshot,thecausemaybe.A.highmicaconditionB.lowambienttemperatureC.cloggedventilationductsD.anopenintheshuntfield注：直流電機(jī)運(yùn)行中過(guò)熱，可能是通風(fēng)不良引起的。A為云母過(guò)髙；B為環(huán)境低溫；C為通風(fēng)管道堵塞；D為并激磁場(chǎng)開(kāi)路，故選C2979.2979.Sparkingatthebrushesofarunningmotorcouldbeanindicationof.A.normaloperationB.adirtycommutatorC.increasedbrushcapacityD.watervaporabsorption注：運(yùn)轉(zhuǎn)電機(jī)電刷閃火花，說(shuō)明換向器臟污，故選B2980.Electricalfailuresinmotorsarecausedbythebreakdownofinsulation,whichmaybecausedby.A.penetrationofmoistureB.accumulationofdirtC.overheatingD.alloftheabove.注：絕緣失效引起的電機(jī)電氣故障可能是由浸濕、積污和過(guò)熱造成的，這些均可能造成絕緣失效，故選D2981.2981.UniversalmotorwilloperateonA.C.or