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1、TheTransformeronloadIthasbeenshownthataprimaryinputvoltagecanbetransformedtoanydesiredopen-circuitsecondaryvoltagebyasuitablechoiceofturn’sratio.isavailableforcirculatingaloadcurrentimpedance.Forthemoment,alaggingpowerfactorwillbeconsidered.Thesecondarycurrentandtheresultinga
2、mpere-turnswillchangetheflux,tendingtodemagnetizethecore,reduceandwithit.Becausetheprimaryleakageimpedancedropissolow,asmallalterationtowillcauseanappreciableincreaseofprimarycurrentfromtoanewvalueofequalto.Theextraprimarycurrentandampere-turnsnearlycancelthewholeoftheseconda
3、ryampere-turns.Thisbeingso,themutualfluxsuffersonlyaslightmodificationandrequirespracticallythesamenetampere-turnsasonnoload.Thetotalprimaryampere-turnsareincreasedbyanamountnecessarytoneutralizethesameamountofsecondaryampere-turns.Inthevectorequation,;alternatively,.Atfulllo
4、ad,thecurrentisonlyabout5%ofthefull-loadcurrentandsoisnearlyequalto.Becauseinmindthat,theinputkVAwhichisapproximatelyisalsoapproximatelyequaltotheoutputkVA,.Thephysicalcurrenthasincreased,andwithintheprimaryleakagefluxtowhichitisproportional.Thetotalfluxlinkingtheprimary,issh
5、ownunchangedbecausethetotalbacke.m.f.,()isstillequalandoppositeto.However,therehasbeenaredistributionoffluxandthemutual11componenthasfallenduetotheincreaseofwith.Althoughthechangeissmall,thesecondarydemandcouldnotbemetwithoutamutualfluxande.m.f.alterationtopermitprimarycurren
6、ttochange.Thenetfluxlinkingthesecondarywindinghasbeenfurtherreducedbytheestablishmentofsecondaryleakagefluxdueto,andthisopposes.Althoughandareindicatedseparately,theycombinetooneresultantinthecorewhichwillbedownwardsattheinstantshown.Thusthesecondaryterminalvoltageisreducedto
7、whichcanbeconsideredintwocomponents,i.e.orvectorially.Asfortheprimary,isresponsibleforasubstantiallyconstantsecondaryleakageinductance.Itwillbenoticedthattheprimaryleakagefluxisresponsibleforpartofthechangeinthesecondaryterminalvoltageduetoitseffectsonthemutualflux.Thetwoleak
8、agefluxesarecloselyrelated;,forexample,byitsdemagnetizingactiononhas