Principle
Electriclocomotivesobtainelectricenergyfromthecontactnet,andtheelectriccurrentsuppliedbythecontactnettotheelectriclocomotivehastwotypes:DCandAC.Duetothedifferentcurrentsystems,theelectriclocomotivesusedarealsodifferent.Basically,theycanbedividedintothreecategories:direct-DCelectriclocomotives,AC-DCelectriclocomotives,andAC-DC-ACelectriclocomotives.
Direct-DCelectriclocomotivesarepoweredbyadirectcurrentsystem,andarectifierdeviceisinstalledinthetractionsubstation,whichconvertsthree-phasealternatingcurrentintodirectcurrentbeforesendingittothecontactnetwork.Therefore,theelectriclocomotivecandirectlyobtainDCpowerfromthecontactnetworkandsupplytheDCseries-excitedtractionmotortouse,whichsimplifiestheequipmentonthelocomotive.Thedisadvantageofthedirectcurrentsystemisthatthevoltageofthecontactnetislow,generallyl500Vor3000V,andthecontactwireisrequiredtobeverythick,whichconsumesalargeamountofnon-ferrousmetalsandincreasestheconstructioninvestment.
History
In1866,GermanengineerSiemensandtechnicianHalluschkajointlyestablishedanelectricmotorcompany,inventedapowerfulgasgenerator,andmadetheworld'sfirstelectriclocomotive.ItwasexhibitedattheParisExpositionthefollowingyearandshockedmanypeople.In1879,attheBerlinIndustryandCommerceFair,theworld'sfirstelectrictrainwasputintopublictrialoperation.Thetrainisdrawnbyanelectricmotor,andtheelectriccurrentisconveyedbytheelectrifiedrail.Thepoweris3horses.Itcantransport18passengersatatimeandthespeedis7kilometersperhour.Twoyearslater,in1881,asmall-scaletramroutewaslaidoutinthesuburbsofBerlin,butitwastheworld'sfirstcommercialtramroute.Atthesametime,Germanysuccessfullytestedthepowersupplysystemwithcontactwiresintheair,whichturnedthepowersupplylinesofelectriclocomotivesfromthegroundtotheair,andthevoltageandpowerofthelocomotivesweregreatlyimproved.
In1895,thefirstlong-distanceelectriclocomotiveappearedontheBaltimore-OhioRailwaylineintheUnitedStates.Thelocomotiveweighs96tons,has1,080horses,anduses550VDCpowersupply.
In1901,electriclocomotivesmanufacturedbySiemensandHalluschkaMotorCompanysetarecordof160kilometersperhournearBerlin.
Atthesametime,in1880,EdisonintheUnitedStatesalsoconductedanexperimentonelectriccars.
China'sfirstelectriclocomotivewasborninZhuzhou,Hunanin1958,named"Shaoshan",andmadegreatcontributionstotheelectrificationofChineserailways.
Electriclocomotivesaredevelopingrapidlyduetotheirfastspeed,strongclimbingability,hightractionandnoairpollution.Theundergroundrailwayalsodevelopedwiththeadventoftrams.
Themainelectriclocomotivesinoperationinmycountryare:
Shaoshan(SS)1SS3SS4(G)SS6SS6BSS7SS7C/D/ESS8SS9(G)
Harmony(HXD)1HXD3DJ1