Short circuit - Wikipedia

A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current ... Shortcircuit FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Electricalcircuitwithnegligibleimpedance Forotheruses,seeShortcircuit(disambiguation). Thisarticleneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingcitationstoreliablesources.Unsourcedmaterialmaybechallengedandremoved.Findsources: "Shortcircuit" – news ·newspapers ·books ·scholar ·JSTOR(July2019)(Learnhowandwhentoremovethistemplatemessage)Treelimbscauseashortcircuit,triggeringanelectricalarcduringastorm Ashortcircuit(sometimesabbreviatedtoshortors/c)isanelectricalcircuitthatallowsacurrenttotravelalonganunintendedpathwithnoorverylowelectricalimpedance.Thisresultsinanexcessivecurrentflowingthroughthecircuit. Theoppositeofashortcircuitisan"opencircuit",whichisaninfiniteresistancebetweentwonodes. Contents 1Definition 2Examples 3Damage 4Relatedconcepts 5Seealso 6References 7Externallinks Definition[edit] Ashortcircuitisanabnormalconnectionbetweentwonodesofanelectriccircuitintendedtobeatdifferentvoltages.ThisresultsinanelectriccurrentlimitedonlybytheThéveninequivalentresistanceoftherestofthenetworkwhichcancausecircuitdamage,overheating,fireorexplosion.Althoughusuallytheresultofafault,therearecaseswhereshortcircuitsarecausedintentionally,forexample,forthepurposeofvoltage-sensingcrowbarcircuitprotectors. Incircuitanalysis,ashortcircuitisdefinedasaconnectionbetweentwonodesthatforcesthemtobeatthesamevoltage.Inan'ideal'shortcircuit,thismeansthereisnoresistanceandthusnovoltagedropacrosstheconnection.Inrealcircuits,theresultisaconnectionwithalmostnoresistance.Insuchacase,thecurrentislimitedonlybytheresistanceoftherestofthecircuit. Examples[edit] Acommontypeofshortcircuitoccurswhenthepositiveandnegativeterminalsofabatteryareconnectedwithalow-resistanceconductor,likeawire.Withalowresistanceintheconnection,ahighcurrentwillflow,causingthedeliveryofalargeamountofenergyinashortperiodoftime. Ahighcurrentflowingthroughabatterycancausearapidincreaseoftemperature,potentiallyresultinginanexplosionwiththereleaseofhydrogengasandelectrolyte(anacidorabase),whichcanburntissueandcauseblindnessorevendeath.Overloadedwireswillalsooverheatcausingdamagetothewire'sinsulation,orstartingafire.Highcurrentconditionsmayalsooccurwithelectricmotorloadsunderstalledconditions,suchaswhentheimpellerofanelectricallydrivenpumpisjammedbydebris;thisisnotashort,thoughitmayhavesomesimilareffects. Inelectricaldevices,unintentionalshortcircuitsareusuallycausedwhenawire'sinsulationbreaksdown,orwhenanotherconductingmaterialisintroduced,allowingchargetoflowalongadifferentpaththantheoneintended. Inmainscircuits,shortcircuitsmayoccurbetweentwophases,betweenaphaseandneutralorbetweenaphaseandearth(ground).Suchshortcircuitsarelikelytoresultinaveryhighcurrentandthereforequicklytriggeranovercurrentprotectiondevice.However,itispossibleforshortcircuitstoarisebetweenneutralandearthconductorsandbetweentwoconductorsofthesamephase.Suchshortcircuitscanbedangerous,particularlyastheymaynotimmediatelyresultinalargecurrentandarethereforelesslikelytobedetected.Possibleeffectsincludeunexpectedenergisationofacircuitpresumedtobeisolated.Tohelpreducethenegativeeffectsofshortcircuits,powerdistributiontransformersaredeliberatelydesignedtohaveacertainamountofleakagereactance.Theleakagereactance(usuallyabout5to10%ofthefullloadimpedance)helpslimitboththemagnitudeandrateofriseofthefaultcurrent. Ashortcircuitmayleadtoformationofanelectricarc.Thearc,achannelofhotionizedplasma,ishighlyconductiveandcanpersistevenaftersignificantamountsoforiginalmaterialfromtheconductorshasevaporated.Surfaceerosionisatypicalsignofelectricarcdamage.Evenshortarcscanremovesignificantamountsofmaterialfromtheelectrodes.Thetemperatureoftheresultingelectricalarcisveryhigh(tensofthousandsofdegrees),causingthemetalonthecontactsurfacestomelt,poolandmigratewiththecurrent,aswellastoescapeintotheairasfineparticulatematter.[1] Damage[edit] Ashortcircuitfaultcurrentcan,withinmilliseconds,bethousandsoftimeslargerthanthenormaloperatingcurrentofthesystem.[2]Damagefromshortcircuitscanbereducedorpreventedbyemployingfuses,circuitbreakers,orotheroverloadprotection,whichdisconnectthepowerinreactiontoexcessivecurrent.Overloadprotectionmustbechosenaccordingtothecurrentratingofthecircuit.Circuitsforlargehomeappliancesrequireprotectivedevicessetorratedforhighercurrentsthanlightingcircuits.Wiregaugesspecifiedinbuildingandelectricalcodesarechosentoensuresafeoperationinconjunctionwiththeoverloadprotection.Anovercurrentprotectiondevicemustberatedtosafelyinterruptthemaximumprospectiveshort-circuitcurrent. Inanimproperinstallation,theovercurrentfromashortcircuitmaycauseohmicheatingofthecircuitpartswithpoorconductivity(faultyjointsinwiring,faultycontactsinpowersockets,oreventhesiteoftheshortcircuititself).Suchoverheatingisacommoncauseoffires.Anelectricarc,ifitformsduringtheshortcircuit,produceshighamountofheatandcancauseignitionofcombustiblesubstancesaswell. Inindustrialandutilitydistributionsystems,dynamicforcesgeneratedbyhighshort-circuitcurrentscauseconductorstospreadapart.Busbars,cables,andapparatuscanbedamagedbytheforcesgeneratedinashortcircuit. Relatedconcepts[edit] Inelectronics,theidealmodel(infinitegain)ofanoperationalamplifierissaidtoproduceavirtualshortcircuitbetweenitsinputterminalsbecausenomatterwhattheoutputvoltageis,thedifferenceofpotentialbetweenitsinputterminalsiszero.Ifoneoftheinputterminalsisconnectedtotheground,thentheotheroneissaidtoprovideavirtualgroundbecauseitspotentialis(ideally)identicaltothatoftheground.[3][4]Anidealoperationalamplifieralsohasinfiniteinputimpedance,sounlikearealshortcircuit,nocurrentflowsbetweentheterminalsofthevirtualshort.[5] Seealso[edit] Electronicsportal Annealingbyshortcircuit Breakingcapacity Conditionalshort-circuitcurrent Short-circuittest Otherelectricalfaults: Groundfault Ohm'slaw Overcurrent,electricaloverload References[edit] ^"LabNote#105ContactLife-Unsuppressedvs.SuppressedArcing".ArcSuppressionTechnologies.April2011.RetrievedFebruary5,2012. ^Bhatia,A."IntroductiontoShortCircuitAnalysis"(PDF).PDHonline.sec.Whatcausesashortcircuit?.Retrieved3July2019.Laysummary–CourseE204. ^BasicElectronics.I.K.InternationalPvtLtd.March2011.pp. 184–.GGKEY:9NLKFQ9D0F2.Retrieved20April2011. ^RobertSpence(5September2008).IntroductoryCircuits.JohnWileyandSons.pp. 99–.ISBN 978-0-470-77971-2.Retrieved20April2011. ^U.A.Bakshi;A.P.Godse(1January2010).LinearIntegratedCircuits.TechnicalPublications.pp. 4–.ISBN 978-81-8431-773-2.Retrieved20April2011. Externallinks[edit] LookupshortcircuitinWiktionary,thefreedictionary. WikimediaCommonshasmediarelatedtoShortcircuit. TroubleshootingStrategyforUS/CanadianHomesfromTheCircuitDetective AuthoritycontrolGeneral IntegratedAuthorityFile(Germany) Nationallibraries France(data) UnitedStates Other MicrosoftAcademic Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Short_circuit&oldid=1044221090" Categories:ElectricityElectricalengineeringSafetyFirepreventionFireprotectionHiddencategories:ArticleswithshortdescriptionShortdescriptionisdifferentfromWikidataArticlesneedingadditionalreferencesfromJuly2019AllarticlesneedingadditionalreferencesCommonscategorylinkfromWikidataArticleswithGNDidentifiersArticleswithBNFidentifiersArticleswithLCCNidentifiersArticleswithMAidentifiers Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk Variants expanded collapsed Views ReadEditViewhistory More expanded collapsed Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Inotherprojects WikimediaCommons Languages العربيةAzərbaycancaবাংলাБеларускаяБългарскиCatalàČeštinaDanskDeutschEestiΕλληνικάEspañolEsperantoEuskaraفارسیFrançaisՀայերենहिन्दीHrvatskiBahasaIndonesiaÍslenskaItalianoעבריתҚазақшаKreyòlayisyenKurdîLietuviųMagyarМакедонскиBahasaMelayuNederlands日本語NorskbokmålOʻzbekcha/ўзбекчаPolskiPortuguêsRomânăРусскийSimpleEnglishSlovenčinaСрпски/srpskiSuomiSvenskaதமிழ்Татарча/tatarçaไทยTürkçeУкраїнськаTiếngViệt粵語中文 Editlinks