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1、PEC电气工程专业英语证书考试-GlossaryofElectricalEngineeringTerms3oAmpereThemeasurementofintensityofrateofflowofelectronsinanelectriccircuit.AnampereistheamountofcurrentthatwillflowthrougharesistanceofoneohmunderapressureofonevoltoAmpereRatingThecurrent-carryingcapacityofafuse.Whenafusei
2、ssubjectedtoacurrentaboveitsampererating,itwillopenthecircuitafterapredeterminedperiodoftimeoAmpereSquaredSeconds,l2tThemeasureofheatenergydevelopedwithinacircuitduringthefuse’sclearing.Itcanbeexpressedas“Meltingl2t”,“Arcingl2t”orthesumofthemas“Clearingl2t”.“l”standsforeffec
3、tivelet-throughcurrent(RMS),whichissquared,and“t”standsfortimeofopening,inseconds.oArcingTimeTheamountoftimefromtheinstantthefuselinkhasmelteduntiltheovercurrentisinterrupted,orclearedoCartridgeFuseAfuseconsistingofacurrentresponsiveelementinsideafusetubewithterminalsonbothe
4、ndsoClassCC Fuses600V,200,000ampereinterruptingrating,branchcircuitfuseswithoveralldimensions.Theirdesignincorporatesarejectionfeaturethatallowsthemtobeinsertedintorejectionfuseholdersandfuseblocksthatrejectalllowervoltage,lowerinterruptingrating fuses.oClassGFuses20A@600VAC
5、,25-604@480VAC,100,000ampereinterruptingratingbranchcircuitfusesthataresizerejectingtoeliminateoverfusing.Theseareavailableinratingsfrom1ampthrough60amps.ClassHFuses250Vand600V,10,000ampereinterruptingratingbranchcircuitfusesthatmayberenewableornon-renewable.Theseareavailabl
6、einampereratingsof1ampthrough600amps.oClassJFusesThesefusesareratedtointerruptaminimumof200,000amperesAC.Theyarelabelledas“Current-Limiting”,areratedfor600voltsAC,andarenotinterchangeablewithotherclasses.oClassKFusesThesearefuseslistedasK-1,K-5,orK-9fuses.Eachsubclasshasdesi
7、gnatedI2tandlpmaximums.ThesearedimensionallythesameasClassHfuses,andtheycanhaveinterruptingratingsof50,000,100,000,or200,000amps.Thesefusesarecurrent-limiting.However,theyarenotmarked“current-limiting”ontheirlabelsincetheydonothavearejectionfeature.oClassLFusesThesefusesarer
8、atedfor601through6000amperes,andareratedtointerruptaminimumof200,000amperes