《航空专业英语》-Unit12

1ElectricalSystems（SeeFig.12.1）1.1ACandDCElectricalPowerACelectricalpowerforairplanegroundoperationsissuppliedthroughtheexternalpowerpanelorfromtheAuxiliaryPowerUnit（APU）drivengenerator.ForinflightoperationpowerissuppliedfromanIntegratedDriveGenerator（IDG）mountedoneachengineorfromtheAPUdrivengenerator.Thepowersourcesarenon-parallel-able.MajorcomponentsassociatedwiththeACsysteminclude：3GeneratorControlUnits（GCUs）,BusPowerControlUnit（BPCU）andpowerpanelslocatedinthemainequipmentcenter.NormalairplaneDCpowerisproducedbyAC/DCconversion.下一页返回1ElectricalSystemsBatterysystemsprovidealternateDCandstandbypower.MajorDCsystemcomponentsinclude：themainbattery,batterycharger,twotransformerrectifierunitsandstaticinverterlocatedinthemainequipmentcenter.LocatedintheaftequipmentcenterarethecomponentsusedwiththeAPUDCsystem：theAPUbatteryandbatterycharger.Anadditionalelectricalgeneratorsystemoperatesasanon-timelimitedbackupsourceintheeventoflossofallthemainelectricalpower.Thegeneratorprovidespowerforthestandbysystem,captain’sflightinstruments,andselectednavigation,communication,lightingandanti-icingloads.上一页下一页返回1ElectricalSystemsThebasicsystemhardwareconsistsofthehydraulicmotorgeneratorandgeneratorcontrolunit.1.2SystemControlandIndicationManualorautomaticsourceselectionisprovidedduringgroundandinflightoperationsfromtheelectricalsystemandauxiliaryelectricalsystemcontrolpanelslocatedintheflightcompartment.Amomentarytestswitchisprovidedforhydraulicmotorgeneratorsystemcheckout.ElectricalsystemmonitoringisdisplayedontheEICAS.上一页返回2ElectricalPowerSystems（SeeFig.12.2）2.1GeneralTheelectricalpowersystemconsistsofbothIl5and28voltACandDCdistributionbuses.2.2ACPowerThemainACbusessupplyalloftheessentialACloadsintheairplane.Eachbusisdividedintoindependentsections.AnACtiebusprovidesinterconnectionbetweenthemainbusesundercertainconditions.Theutilitybusessupplynon-essentialloadssuchaspassengerentertainmentandreadinglights.Galleypowerisalsoconsideredasthenon-essentialload.下一页返回2ElectricalPowerSystemsThenon-essentialloadcanbede-energizedautomaticallyforloadsheddingpurposes.TheAPUstartermotorisenergizedbytheAPUT-RunitiftherightmainACbusisenergizedduringAPUstarting.Thegroundservicebussuppliesbothinflightandgroundloadthatincludeinteriorlights,batterychargersandcoolingfans.Thegroundhandlingbussuppliesloadssuchascargohandlingequipmentthatisusedonlyduringgroundperations.Thisbusisonlypoweredontheground.上一页下一页返回2ElectricalPowerSystemsThecenterbusessupplybothACandDCpowertothecenterchannelequipmentoftheautolandsystem.DuringcategoryIIIautolandoperation,thebusesaresuppliedfromalternatesourcesindependentofthemainbuses.Theflightinstrumenttransferbusessupplypowertotheselectedcaptain’sandfirstofficer’sflightinstrumentandallowautomatictransfertoanalternatepowersourceincaseofnormalsourcefailure.TheACstandbybussuppliessinglephasepowertoessentialflightloadsandwillautomaticallytransferpowersourcesincaseofprimarysourceloss.上一页下一页返回2ElectricalPowerSystems2.3DCPowerTheleftandrightDCbusessupplypowertothoseloadsrequiringDCpower.EachmainDCbusisdividedintoindependentsections.Wheneitherbusisunpowered,theDCtiecontrolunitautomaticallyenergizestheDCtierelay.TheDCstandbybussuppliespowertocertainessentialairplaneloadsandwilltransfersourcesincaseofprimarysourceloss.TheDCgroundhandlingbussuppliesDCpowerforgroundhandlingequipmentandisenergizedonthegroundonly.上一页下一页返回2ElectricalPowerSystemsAmainbattery/batterychargersystemprovidesadedicatedsourceofpowerfortheoperationofthestandbyandautolandsystems.TheseparateAPUbattery/batterychargersystemprovidespowerforAPUstarting.2.4HydraulicMotorGeneratorSystemsThehydraulicmotorgeneratorsystemprovidesanon-timelimitedalternatesourceofACandDCpowerafterthelossofallgeneratorpower.AnACgeneratorsuppliescaptain’sflightinstrument,leftandrighttransferbuses.ADCgeneratorcanpowerthehotbatterybus.上一页返回3ElectricalSystemPanels（SeeFig.12.3）3.1GeneralThenormaloperationoftheelectricalpowersystemisperformedattheelectricalsystemcontrolpanelandtheauxiliaryelectricalsystemcontrolpanel.Bothmomentaryandalternateactionpushbuttonswitchesareusedontheelectricalpanels.Thealternateactionswitchismechanicallylatchedtothelastoperatedposition（“inorout”）.Switchpositionisindicatedbytheabsenceorpresenceofamechanicalflagintheswitchface.Allindicatorlightsarepoweredviathemasterdimandtestsystem.3.2ElectricalSystemControlPanel（P5）下一页返回3ElectricalSystemPanelsThemomentaryexternalpowerswitchcontrolstheopening/closingoftheexternalpowercontactor.AwhiteAVAILlightindicatespowerisofproperquality.ThewhiteONlightilluminateswhenevertheexternalpowercontactorisclosed.Thegeneratorcontrolswitchesprovideacontrolsignalwhichcausestheclosingofthegeneratorcontrolrelay（GCR）,andwhenproperpowerisavailable,itenablestheautomaticclosingofthegeneratorcircuitbreaker（GCB）.TheflowbarandONlegendindicateswitchposition.AnamberOFFlightilluminateswhentheassociatedgeneratorcircuitbreakerisopen.上一页下一页返回3ElectricalSystemPanelsTheACbustieswitchesallowthemanualorautomaticcontrolofthebustiebreaker（BTB）.IntheunlatchedpositiontheassociatedBTBwillbeopened,isolatingtheassociatedmainACbusfromtheACtiebus.TheAUTOindicationwillnotbevisibleandtheamberISLNlightwillbeilluminated.Operatingtheswitchtothelatchedinposition,normallyAUTOilluminatesandISLNextinguishes,willenabletheautomaticoperationofthebustiebreaker.IfISLNilluminateswhenbustieswitchislatched,thenafaulthastrippedandlockedtheBTBopen.ACBUSOFFindicatorlightilluminateswhenmainACbusisde-energized.上一页下一页返回3ElectricalSystemPanelsThelatchingutilitybusswitchesprovidethemanualcontrolofthepowerrelaysconnectingutilityandgalleybusestotheleftandrightmainACbuses.TheONlegendindicatesswitchpositionandishiddenwhentheswitchisintheunlatchedposition.TheamberOFFlightilluminatesiftheassociatedutilitybusrelayisopen.Themomentarygeneratordrivedisconnectswitchescauseamechanicaldisconnectionbetweentheintegrateddrivegeneratorandtheengine.Theswitchesarespringloadedtothe“out”position.AnamberDRIVElightilluminatesforeitherhighoiltemperatureorlowoilpressureintheintegrateddrivegenerator.上一页下一页返回3ElectricalSystemPanelsThebatteryswitchcontrolstheconnectionofthebatterybustothehotbatterybus.TheONlegendindicatestheswitchpositionandishiddenwhentheswitchisintheunlatchedposition.AnamberOFFlightilluminateswhenthebatteryswitchisintheunlatchedpositionduringnormalgroundandflightoperations.Abatterydischargelightilluminatesifthebatteryisdischarging.Thestandbypowermodeofoperationiscontrolledbythestandbypowerselectorswitch.TheswitchmustbepushedintoturnfromAUTOtoOFFposition.AnamberstandbypowerbusofflightwillilluminatewhentheACorDCstandbybusisunpowered.上一页返回4BiteDisplays-Bit（SeeFig.12.4）4.1PowerRequirementsTheBITEtestscanbeperformedwiththeairplanecomplexlypoweredorwithonlythebatteryswitchlatchedtoON.4.2Built-inTest（BIT）SwitchesTheBITswitch,whenpushed,retrievesthefaultmessagesstoredinNVMthataretheresultofoperationalBITE.Thesystemmessageisdisplayedfor2seconds.Thefaultmessageisdisplayedfor15seconds,identifiesanyprotectiontriporstatusmonitorfault,andthenwillattempttoidentifythefailedcomponentorcircuit.下一页返回4BiteDisplays-BitThefailedcomponentorcircuitmessageisdisplayedfor15seconds.Ifthereisnofaultdatumstoredforaflight,anOKisdisplayedfor2seconds.ThefaultdatafrompreviousflightsareretrievedbypushingtheBITswitchduringthe15secondsthatFORPREVIOUSFLTPUSHNOWmessagedisplays.Previousflightdataareretrievableforuptosixflights.ForthemessagesthatidentifytheGCUorEPCUasfailed,ahexadecimalcodenumberisdisplayed.上一页返回5IntegratedDriveGenerators（SeeFig.12.5）5.1PurposeTheintegrateddrivegeneratorproduces115/200voltAC,threephase,400hertzpower.5.2LocationTheIDGislocatedontheaftleftsideoftheengine-drivengearbox.5.3PhysicalDescription/Features5.3.1IDGHousingandWeightTheIDGhousingisatwo-piecemagnesiumcastingwithsingleboltedinterface.ThedryweightoftheIDGis117.7pounds.下一页返回5IntegratedDriveGenerators5.3.2ElectricalConnectorsTwoelectricalconnectorsinterfacewithairplanewiringforcontrol,protectionandmonitoringcircuits.ConnectorAprovideselectricalconnectionforthepermanentmagnetgenerator（PMG）,chargepressureswitchandoiltemperaturebulbs.Theinputspeedsensor,disconnectsolenoid,internalcurrenttransformerassemblyandexciterfieldareconnectedthroughconnectorB.AllwiringbetweenIDGcomponentsislocatedwithinthehousing.5.3.3TerminalBlocks上一页下一页返回5IntegratedDriveGeneratorsThemaingeneratorstator3-phaseoutputandneutraloutputleadsareterminatedata4-studterminalblock.Thestudsare3/8"diameterstainlesssteel.Theneutraloutputisgroundedtotheupperstrutstructure.5.3.4SplinesAmalesplineontheinputdriveshaftprovidestheengineaccessorygearboxconnection.Theshearsectionisdesignedtobreakwithaninputtorque9,000±400inchpounds.Areplaceablesplinemuffisattachedtothedriveshaftbyasinglescrew.上一页下一页返回5IntegratedDriveGenerators5.3.5DisconnectResetRingsItallowsgroundonlyrestorationofengineaccessorygearboxandIDGinputsplinemechanicalconnection,byresettingaspring-loadedsplit-nutpawl.5.3.6OilPortsTheoil-inandoil-outportsprovidetheinterfacebetweentheIDGandtheexternaloilcoolingsystem.5.3.7Drain,FillandVentPortsOilisdrainedfromtheIDGcasebytheremovalofthecasedrainplug.上一页下一页返回5IntegratedDriveGeneratorsThepressurefillfittingconnectstothepressurefillportforthepressurefillingoftheIDG.Theoverflowdrainconnectstoaninternalstandpipe,andisusedduringservicing.Undernormaloperatingconditionsthecasepressureisintherangeof5to10psig.5.3.8ChargePressureTestPortsThechargepressuretestportprovidesamonitoringpointforchargepumppressure.5.3.9CaseThermalReliefValvesThecasethermalreliefvalveallowshotIDGoiltodrainoverboardduringover-temperatureconditions.上一页下一页返回5IntegratedDriveGenerators5.3.10OilLevelIndicatorsThelowoillevelindicatorisaprismaticsightglasswithdisplaysectionwhichprovidesvisualindicationwhentheIDGoilisbelowtheaddlevel.5.3.11ScavengeFiltersandDeltaPressureIndicatorsAnon-bypassingfilteronthedischargesideofthescavengepumpsfiltersalloilflowleavingtheIDG.Thescavengefiltercontainsapop-updeltapressureindicator.Aredbuttonpopsoutwhenthepressuredropreaches60psi.Thedifferentialpressureindicatorislockedoutbelow145°F（63℃）topreventnuisancetripping.上一页下一页返回5IntegratedDriveGeneratorsIDGSERVICEACCESS（SeeFig.12.6）ServicingAhingedIDGaccessdoorislocatedontheinnerductoftheleftthrustreversercowl.ThisdoorallowsIDGservicingusingthepressurefillandoverflowdrainconnections.上一页返回6IDGServicing（SeeFig.12.7）6.1OilLevelCheckNOTE：DONOTCHECKOILLEVELIFTHEIDGISDISCONNECTED.REFERTO24-20-00FAULTISOLATIONANDCORRECTFOR“DISCONNECTTRIP”BITEMESSAGE.Anoillevelcheckshouldfollowanymaintenanceactionthatresultsinthelossofoil,ifoillevelcheckisbeingperformedafteraflightorenginerunallows5minutesminimumstabilizationtimefollowingengineshutdownbeforeperformingoillevelcheck.Whentheoillevelindicatorisviewedattheobserverviewingangle,thewhitemarksshouldalign.Oilreplenishmentisrequired下一页返回6IDGServicingwheneveroilisnotvisibleovertheentireviewingareaoftheindicator.6.2IntegratedDriveGeneratorOilServicingIftheIDGisbeingservicedduetooillossduringsystemmaintenance,drainIDGcaseandthencontinueservicing.IftheIDGbeingservicedforanyotherreason,drainingisnotrequired.Apressurefillservicingcartcapableofpumpingoilat5to15psiwithanOzoneOMP2506-3couplingonthefillhouseandadrainhosewithanOzoneOMP2505-3couplingisrequired.上一页下一页返回6IDGServicingRemovetheprotectivecoverfromthepressurefil1valveandconnectthepressurefillhose.Removetheprotectivecoverfromtheoverflowdrainvalveandconnectthedrainhose.CAUTION：WHENSERVICINGTHEIDG,DONOTMIXTYPESORBRANDSOFOIL.MIXINGOILCOULDCAUSEDAMAGETOTHEIDG.CAUTION：CHECKTHATOIL-DRAINHOSEISLOWERTHANTHEIDGATALLPOINTS.HOLDINGHOSEABOVETHEIDGWILLGIVEINCORRECTIDGOILLEVEL.THISCOULDRESULTINANOVERFILLEDCONDITIONANDCAUSEDAMAGETOTHEIDG.上一页下一页返回6IDGServicing6.3PumpoilfromservicecartintotheIDGCAUTION：SOONAFTERSTARTINGTOPUMPOILINTOTHEIDG,OILMAYFLOWFROMTHEOIL-DRAINHOSE.THISDOESNOTINDICATEAFULLIDG.CONTINUESERVICINGUNTILAMINIMUMOFONEQUART（ONELITER）OFOILHASOVERFLOWEDINTOTHECONTAINER.THISISREQUIREDTOASSURETHEIDGOVERFLOWDRAINCOUPLINGISFULLYATTACHED.FAILURETOOBTAINNEEDEDDRAINAGECANRESULTINOVERFILLINGANDCAUSEDAMAGETOTHEIDG.上一页下一页返回6IDGServicingImmediatelyremovethepressurefillhosefromthefillvalvewhenaminimumofonequart(oneliter)hasoverflowedintocontainer.Whentheoilfromtheoverflowdrainhosesubsidestoslowdrippingcondition,removethedrainhose.Installprotectivecovers.6.4ChangingtheIDGOilThisprocedureisusedwhenanoilchangeisrequiredduetoanoilsamplecheck,scavengefilterinspection,orbyanoperator.上一页下一页返回6IDGServicingDraintheIDGbeforechangingtheoilorbeforeremovingtheIDGfromtheenginegearbox.DepressurizetheIDGbyconnectingdrainlinetotheoverflowdrainvalve.RemovecasedrainplugandO-ring.Allowoiltodrainintoasuitablecontainer（1gallon）.PumpoilfromservicecartintotheIDGuntiladditional1to1.5gallonsarecollectedfromcasedrain.Replacescavengefilterandinstallcasedrainplug.ServicetheIDGusingIntegratedDriveGeneratoroilservicingprocedure.上一页下一页返回6IDGServicing6.5ScavengeFilterCheckIftheredbuttononthedeltapressureindicatorisextended,checkthefilterelement.Checkscavengefilterelementfordamage,collapse,ori