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1、2013年初级电工证考试试题（2013primaryelectriciancertificateexaminationquestions）2013primaryelectriciancertificateexaminationquestionsFirst,thenounexplanation:1,three-phasealternatingcurrent:anelectricsystemconsistingofthreealternatingcircuitswiththesamefrequency,amplitude,amplitude,ph
2、asedifference,mutualdifferenceof120degreesangle,calledthree-phasealternatingcurrent.2.Primaryequipment:equipmentdirectlyrelatedtotheproductionofelectricalenergyandpowertransmissionanddistributioniscalledprimaryequipment.Itincludesallkindsofhighvoltagecircuitbreakers,isolati
3、ngswitches,buses,powercables,voltagetransformers,currenttransformers,reactors,arresters,arcsuppressioncoils,shuntcapacitorsandhighvoltagefuses.3andtwoequipment:auxiliaryequipmentformonitoring,measuring,controlling,controllingandprotectingprimaryequipment.Suchasvariousrelays
4、,signaldevices,measuringinstruments,recordingandrecordingdevices,telemetryandremotesignalingdevices,variouscontrolcables,andsmallbuses.4,highvoltagecircuitbreakerandhigh-voltageswitch,itcannotonlycutofftheloadcurrentandloadcurrenthighvoltagecircuitorclosed,andwhenafaultoccu
5、rs,theeffectoftherelayprotectiondevice,cutofftheoverloadcurrentandshort-circuitcurrent.Theutilitymodelhastheadvantagesofperfectarcextinguishingstructureandsufficientinterruptingcapacity.5、loadswitch:thestructureoftheloadswitchissimilartothesecretisolatingswitch,butonlyasimp
6、learcextinguishingdeviceisinstalled.Italsohasanobviousdisconnectionpoint,hasacertainabilitytobreakdown,canbeloadedwithoperation,butcannotdirectlydisconnecttheshort-circuitcurrent,ifnecessary,relyontheseriesofhigh-voltagefusestoachieveit.6,aircircuitbreaker(automaticswitch)i
7、samanual:(orelectric)closing,keepclosingpositionforlocking,lowvoltageswitchtrippingmechanismbyactingonthetripandhasanarcextinguishingdevice,iswidelyusedinACandDCdeviceinthe500Vbelow,whenthecircuitoverload,shortcircuit,voltagedropordisappear,canautomaticallycutoffthecircuit.
8、7:Cable:thecorewire(conductivepart),plusinsulationlayerandprotectivelayerofthreepa
