变压器-外文翻译.doc

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1、外文翻译TransformerATransformerisadevicethatchangeacelectricenergyatonevoltagelevelintoacelectricenergyatanothervoltagelevelthroughtheactionofamagneticfiled.Itconsistsoftwoormorecoilsofwirewrappedacommonferromagneticcore.Thesecoilsare(usually)notdirectlyconnected.Theonlyconnectionbetweenthecoilsisth

2、ecommonmagneticfluxpresentwithinthecore.Oneofthetransformerwindingsisconnectedtoasourceofacelectricpower,andthesecond(andperhapsthird)transformerwindingsupplieselectricpowertoloads.Thetransformerwindingconnectedtothepowersourceiscalledtheprimarywindingorinputwinding,andthewindingconnectedtothelo

3、adsiscalledthesecondarywindingoroutputwinding.Ifthereisathirdwindingonthetransformer,itiscalledthetertiarywinding.Powertransformersareconstructedononeoftwotypesofcores.Onetypeofconstructionconsistsofasimplerectangularlaminatedpieceofsteelwiththetransformerwindingswrappedaroundtwosidesoftherectan

4、gle.Thistypeofconstructionisknownascoreform.Theothertypeconsistsofathree-leggedlaminatedcorewiththewindingswrappedaroundthecenterleg.Thistypeofconstructionisknownasshellform.Ineithercase,the7外文翻译coreisconstructedofthinlaminationselectricallyisolatedfromeachotherinordertoreduceeddycurrentstoamini

5、mum.Powertransformersaregivenavarietyofdifferentnames,dependingontheiruseinpowersystems.Atransformerconnectedtotheoutputofageneratorandusedtostepitsvoltageuptotransmissionlevelsissometimescalledaunittransformer.Thetransformerattheotherendofthetransmissionline,whichstepsthevoltagedownfromtransmis

6、sionlevelstodistributionlevels,iscalledasubstationtransformer.Finally,thetransformerthattakesthedistributionvoltageandstepsitdowntothefinalvoltageatwhichthepowerisactuallyusediscalledadistributiontransformer.Allthesedevicesareessentiallythesametheonlydifferenceamongthemistheirintendeduse.Inaddit

7、iontothevariouspowertransformers,twospecial-purposetransformersareusedwithelectricmachineryandpowersystems.Thefirstofthesespecialtransformersisadevicespeciallydesignedtosampleahighvoltageandproducealowsecondaryvoltagedirectl