机械制造类专业英语 教案 Module One Basics in Mechanical Workplace

SessionOneIdentifyinghazardsWhatisahazard?Ahazardisanysituationwiththepotentialtocauseinjuryorillness.Forexample,situationsthatcouldposehazardsinclude:asystemofwork,apieceofmachinery,achemicalthatisused.Toassistyouinthinkingabouthazards,thisLearnerResourcewillbreakhazardsintofivemajorgroups:Physical(e.g.plant/machine,noise,electrical,lighting,radiation,workingatheights,housekeeping)Chemical(e.g.hazardoussubstances,dangerousgoods)Ergonomic(e.g.manualhandling)Psychological(e.g.workstressors)BiologicalSessionTwoThehierarchyofcontrolofhazardsinworkshop1.EliminationControllingrisksthrougheliminationmayinclude,forexample,eliminatingtoxicsubstances,hazardousmachineryorprocessesthatarenotnecessarytothewayworkisperformed.2.SubstitutionSubstitutionmayinclude,forexample,substitutingatoxicsubstance,hazardousmachineryorprocesswithoneknowntobelessharmfultohealthorsafety.3.IsolationIsolationmayinclude,forexample,enclosingorisolatingahazardsuchasatoxicsubstancebyusingafumecupboardorusingsoundenclosureboothstocontrolnoisymachinery.4.EngineeringcontrolsEngineeringcontrolsmayincludechangingprocesses,equipmentortools,forexample:installationofmachineguardsandmachineoperationcontrolsventilationtoremovechemicalfumesanddusts,andusingwettingdowntechniquestominimizedustlevelschanginglayoutofworklevelstominimizebendingandtwistingduringmanualhandling5.AdministrativecontrolsAdministrativecontrolsmayincludechangingworkprocedurestoreduceexposuretoexistinghazards.Forexample:reducingexposuretohazardsbyjobrotationlimitingthenumberofpeopleexposedtothehazardbylimitingaccesstohazardousareas6.PersonalprotectiveclothingandequipmentPersonalprotectiveclothingandequipmentincludedevicesandclothingsuchassafetyclothing,footwear,helmetsandearmuffsthatprovideindividualemployeeswithsomeprotectionfromhazards.WearsafeclothingWearsafeclothingQuizQuestionsTaskOne:True FalseAhazardisanysituationwiththepotentialtocauseinjuryorillness.FORMCHECKBOX FORMCHECKBOXPersonalprotectiveclothingandequipmentareclothinganddevicesthatprovideemployeeswithsomeprotectionfromhazards.FORMCHECKBOX FORMCHECKBOXAdministrativecontrolsmayincludechangingworkprocedurestoreduceexposuretoexistinghazards.FORMCHECKBOX FORMCHECKBOXSessionThreeFirstAidFirstaidis'theprovisionofemergencytreatmentandlifesupportforpeoplesufferinginjuryorillness'.Firstaidaimsto:promoteasafeenvironmentpreservelifepreventinjuryorillnessfrombecomingworsehelppromoterecoveryprotecttheunconsciousreassuretheillorinjuredActivity：Groupdiscussion：contentslistforafirstaidkitSuggestedcontentsforafirstaidkitinclude:SamplecontentslistforafirstaidkitWhilethespecificcontentsofafirstaidkitwillbedeterminedfromariskassessment,thefollowingcontentslistprovidesabasicoutline:emergencyservicestelephonenumbersandaddresses,includinglocaldoctorsandhospitalsnameandtelephonenumberforworkplacefirstaidersbasicfirstaidnotesindividuallywrappedsterileadhesivedressingssterileeyepadssterilecoveringsforseriouswoundstriangularbandagessafetypinssmall,mediumandlargesterileun-medicatedwounddressingsadhesivetapecrepebandagesdisposableglovesscissorsActivity：Groupdiscussion：Whatshouldwehaveinafirstaidroom？FirstaidroomsFollowingarethetypesofcontentsthatmaybeneededinafirstaidroom:resuscitationmasksinkandwashbasinwithhotandcoldwatersuppliedworkbenchordressingtrolleycupboardsforstorageofmedicalsupplies,dressingsandlinensoileddressingcontainerselectricalpowerpointsmedicalexaminationcouchwithblanketsandpillowsuprightchairsremovablescreensdeskandatelephonestretchersfirstaidkitQuizQuestionsTaskOne：Tickthecorrectresponseintherelevantbox.True False1.Thedefinitionoffirstaidis'theprovisionofemergencytreatmentandlifesupportforpeoplesufferinginjuryorillness'.FORMCHECKBOX FORMCHECKBOX2.Oneoftheaimsoffirstaidistopreservelife.FORMCHECKBOX FORMCHECKBOX3.Firstaidcanbeaneffectivealternativetomedicaltreatmentbyadoctor.FORMCHECKBOX FORMCHECKBOXAnswer:1T2T3FTaskTwo：Suggestedcontentsforafirstaidkitinclude:SessionFourEmergencymanagementandfiresafetyThetypesofemergenciesthatcouldoccurataworkplacedependonfactorssuchasthetypeofworkplaceandthelocationoftheworkplace.Thetypesofemergenciesthatcouldoccurinclude:firechemicalspillsorchemicalreleasebombthreatsstructuralfaultsinthebuildingfloodingorseverewaterdamagethreatsofviolenceorrobberyExamplesofsomeoftheemergenciesExamplesofsomeoftheemergenciesFuel+heat+oxygen+chemicalreactionequalsfireSolvent+spark+air+chemical+reaction=fireFiresTopreventorextinguishafire,youneedtoactononeofthefourelementsoffire:sourceofignition/heatfueloxygenchemicalreactionExamplesofhowtopreventfiresinclude:Smokingonlywherepermitted.Large,non-tipashtraysshouldbeusedandeverythinginthemshouldbecoldbeforetheyareemptied.Keepingpassagewaysandexitsfreefromstorageandwasteinordertominimizecombustiblematerial.Promptlyremovingwastepaper,packaging,oldragsandotherfirehazards.Ensuringthatappliances(stoves,kettlesetc)areswitchedoffeachnight.Thisshouldincludecomputersandcomputermonitorsifpossible.Makingsurethatanybrokenelectricalcordsorplugsarereplacedimmediately.Ifanapplianceoritemofequipmentsmellsorgivesoffsmoke,turnitoff,unplugitanddonotuseitagainuntilithasbeencheckedbyaqualifiedtechnician..Ensuringthereisplentyofaircirculationspacearoundheat-producingequipment(suchasphotocopiersandcomputers).QuizQuestionTrueFalse1.Onlyabout6%ofoxygenneedstobepresentintheairforafiretoburn.FORMCHECKBOX FORMCHECKBOX2.Ifanapplianceoritemofequipmentsmellsorgivesoffsmoke,turnitoff,plugitanddonotuseit.FORMCHECKBOX FORMCHECKBOX3.Smokingonlywherepermitted.FORMCHECKBOX FORMCHECKBOX4.Ensuringthatappliancesareswitchedoffeachnight.Thismaynotincludecomputersandcomputermonitorsifpossible.FORMCHECKBOX FORMCHECKBOXAnswer:1F2F3T4FSessionFiveWorkshopDangerousGoodsandStrategiestoControlSymbolsforthedifferentclassesofdangerousgoodsWhatdothesesymbolsmean?Dangerousgoodsaresubstancesthatmaybecorrosive,flammable,explosive,spontaneouslycombustible,toxic,oxidisingorwater-reactive.EffectsonhealthandsafetyThehealthandsafetyeffectsofdangerousgoodsareoftenimmediateandsevere.StrategiestocontroldangerousgoodsThepreferredoptiontocontrolrisksarisingfromtheuseofdangerousgoodsiselimination.Personalprotectiveequipment(PPE)thatincludesoveralls,aprons,gloves,dustmasks,respirators,safetyfootwear,andgogglesorfaceshields.QuizquestionsforLearningTrue False1.Thepreferredmethodofcontrollingrisksarisingfromtheuseofdangerousgoodsisisolation.FORMCHECKBOX FORMCHECKBOX2.PPEstandsforpersonalprotectiveequipment.FORMCHECKBOX FORMCHECKBOXLookatthispicture,whatformsofpersonalprotectiveequipmentdothemanuse?FORMCHECKBOXglovesFORMCHECKBOXoverallsFORMCHECKBOXfaceshieldsFORMCHECKBOXgogglesFORMCHECKBOXrespiratorsAnswer:gloves,overalls,faceshieldSessionSixNoiseAsimpledefinitionofnoiseis'anydisturbingsound'.Inpractice,itisreferredtoas'sound'whenpleasantorneutral,and'noise'whenitisannoyingorirritating.IdentifyinghazardsAsoundlevelmeterbeingusedtotestnoiselevelsAsoundlevelmeterbeingusedtotestnoiselevelsStrategiestocontrolNoisehazardsPersonalProtectiveEquipmentExamplesofpersonalprotectiveequipmentfornoiseExamplesofpersonalprotectiveequipmentfornoiseFollowingaresomespecificexamplesofwaystocontrolnoise1.Eliminateorreplacetheplantoritsoperationwithaquieteroperation.2.Replacenoisyequipmentwithnewerequipmentthatcreateslessnoise.3.Usesoundabsorbingmaterialtoabsorbvibrationandthusreducenoise.4.Enclosenoisymachineryorputbarriersbetweenthemachineryandpeople.5.Reducetheamountoftimepeopleareexposedtonoise,oruseearmuffsQuizquestionsforLearningTrue False1.Asoundlevelmetercanbeusedtotestnoiselevels.FORMCHECKBOX FORMCHECKBOX2.Noisecanonlycauseimmediatehearingloss.FORMCHECKBOX FORMCHECKBOX3.Usesoundabsorbingmaterialtoabsorbvibrationandthusreducenoise.FORMCHECKBOX FORMCHECKBOXAnswer:1T2F3TPARTTWOWorkplaceToolsandMeasuringEquipmentUnitOneWorkplaceToolsI.UNITDESCRIPTIONThisunitidentifiesESP(word,phrasesandpatterns)requiredtoselect,safelyuseandmaintainworkplacetoolsandequipment.II:NOMINALHOURS8HoursIII:TEACHINGOUTCOMEAfterteaching,studentswillbeableto:GraspESPofworkplacetoolsandequipment.Dosomereadingandtranslationconcerned.IV:PRIORKNOWLEDGEHigh-schoolPublicEnglishLevelV:READINGMATERIALS1.WordsandphrasesHandtools---GeneralPrybarApplication:partingcomponent,removingsealsandaligningholesbrush刷子Application:washingcomponentswithsolvent,removingdirtyfromparts.wire钢丝刷Application:removingcarbonrustgasketmaterialdirtfromparts.chisel鉴子Application:cuttingrivetsboltsnutsandsheetsteel.diamond-point钻石刻刀Application:cleaningkeywaysthreadsandcorners.die板牙Application:cuttingexternalthreadsonrodorbolts.diestock板牙板手Application:holdingandrunningadieduringthreadingprocedure.drift孔锤Application:removingsleevesandbushes.Fittingbushesandseals.drill电钻Application:grippingandturningatwistdrill.hand手摇钻Application:asabove.twist钻头Application:boringholesthroughmetal,woodandplastic.extractor---stud麻化锥形钻头Application:Removingbrokenstuds(studmustbedrilledthroughitscentre)flutedandstraight麻花修光钻头Application:Asabovecam夹头Application:Removingbrokenbutprotrudingstud.file(flatandmill)平锉刀Application:Restoringsurfacetoaflatandsmooth.half—round半圆锉刀Application:Enlargingholesandroughfinishingconcavesurface.round(rattail)圆锉刀Application:Enlargingsmallholesorfilingfilles.point鼠尾细锉刀Application:Restoringpointsurfacestocondition.square方锉刀Application:Formingandfinishingelongatednotes.triangle三角锉Application:Restoringdamagedthreads.Sharpeningsawteeth.grinder(portable)便携磨具Application:Reducingthesizeofmetalparts.Cuttingmetalparts.Preparingmetalforwelding.angle角磨具Application:hacksaw手锯Application:Usedforcuttingmostmetalobjects.hammer(ballpeen)圆锤Application:Roundingoffrivetsandbolts.Formingmetal.Drivingdriftspinspunchesandchisels.sledge手用大锤Application:Drivinglargedriftspins,collarsandshafts.softface软锤Application:Hammeringpartsmadefrommaterialsthatbruiseeasilyorhaveaveryhardsurface.electric电加热Application:Joiningsteelorcopperwarewithresincoredsolder.key—allen六角板手Application:Looseningortighteningorsetscrews.leadlight照明灯Application:Illuminatingtheimmediateworkarea.pilers(combinations)钳子Application:Twisting,gripping,bendingandcuttingmostthinsheetmetalsorwires.longnose尖嘴钳Application:Grippingandholdingverysmallpartsorfinewire.multi-grip多口径夹钳Application:Grippingandholdingroundparts.sidecutting切割钳Application:Snippingwire,smallboltsorrodsandsplitpins.Removingandreplacingsplitpins.napring鸭嘴钳Application:Removingandreplacinginternalandexternalcirclips.vicegrip鳄嘴钳Application:Holdingorclampingcomponents.punch(aligning)冲孔器Application:Aligningholesmoreparts.center中心冲孔器Application:Indentingmetalsurfacetolocateatwistdrill.pin针式冲头Application:Removingtaperedorstraightpins.starter启动器Application:Breakingtheinitialgripsofapin.Usedbeforeapinpunch.scraper刮刀Application:Removingcarbonrustandstubborndirtfromflatsurfaces.screwdriver平口螺丝刀Application:Looseningandtighteningscrewswithastandardslotintheirheads.Phillips梅花螺丝刀Application:Looseningandtighteningscrewswitharecessedcrossintheirheads.socketaccessories(bracespeed)手摇驱动器Application:Unscrewingloosebolts.Screwingboltsornutsuntiltheyarejusttight.extension加长杆Application:Locatingthehandleorspeedbraceinapositionthatclearsothercomponentsorbodywork.handle-breakerbar手闸杆Application:Initiallylooseningtightboltsornuts.“D”bar弯拐Application:Initiallylooseningboltsandnuts.slidingtee滑动板手Application:AsaboveratchetApplication:Unscrewingboltsornutswhenspacearoundthemislimited.universaljoint万向节Application:Allowsaslightmisalignmentbetweenahandleandsocket.socket(standard)套筒板牙普通型Application:Usedwithahandletoloosenortightenboltsornuts.extradeep加深型Application:Looseningortighteningcomponentsornutsfittedsomedistancefromtheendoftheirstuds.sparkplug火花塞套筒板手Application:Looseningortighteningsparkplugs.impact冲去套筒Application:Usedwithanimpactwrenchtoloosenortightenboltsornuts.openend(flat)双开口板手Application:Looseningortighteningboltsornutslocatedinaconfinedspace.ring双梅花板手Application:Looseningortighteningboltsornutsthathaveconfinedspaceabovebination两用板手Application:Hastheadvantagesofbothtypesofspanners.tap(hand)丝锥Application:Usingwithahandletocutathreadinaholebooringthroughorintomostmaterials.taphandle(stock)丝锥板手手柄Application:Holdingandturningatapduringathreadingprocess.T型板手Application:Asabove.tinsnips夹钳Application:Shearing(cuttingmostsheetmetalsorthinmaterials.toolbox工具箱Application:Holding,separatingandtransportinghandtools.wrench(adjustable)活动板手Application:Substitutingforthecorrectspanner.pipe管子钳Application:Grippingandturningcylindricalshapes.Handtools---specializedgrease(hand)润滑油枪Application:Lubricatingballjointswithgrease.impactscrewdriver冲去螺丝刀Application:Looseningextremelytightscrews.impactwrench气动板手Application:Removingandreplacingboltsornutsatafastrate.oilfilterremover机油板手Application:Removinganoilfilter.oilgun(hand)手动油枪Application:Withdrawingoilfromacomponentorinsertingoilintoacomponent.pipecutter管子切割器Application:Cuttingtheendofsteelorcoppertubingsothatitissquare.pipefaringtool(single&double)管子扩孔器Application:Formingauniformlip(flare)ontheendofasteelorroppertube(pipe)Formingadoublethicknesslip(flare)ontheendofasteelorcoppertube(pipe)pistonringcompressor活塞环压缩器Application:Clampingpistonringsfirmlyintotheirpistongroovesduringtheinstallationofthepistonintoitsbore.ridgeremover荇磨头Application:Cuttingthelip(ridge)thatisformenonthetopofaworncylinderbore.rotarybrush去积碳刷Application:Usedwithanelectricdrilltoremovecarbonfromthecombustionchambersandportsofacylinderhead.sealpuller油封拉拔器Application:Removingoilseals.steeringwheel转向盘拉拔器Application:Removingsteeringwheels.valvetapper气门研磨具Application:Grippingandturningavalveduringavalvegrindingonacylinderhead.valveseatcutter气门座饺刀Application:Restoringvalveseatsinthecombustionchambersofacylinderhead.valveseathone气门座磨石Application:Usedwithasynchro-seatingunitwhichisdrivenbyanelectricdrillforcuttingandhoningvalvesseatsinacylinderheadtothedesiredshape.wheelcylinderclamp车轮卡钳Application:Holdingwheelcylinderpistonsintheirboreswhilethebrakeshoesandreturnspringshavebeenremoved.wheel(hub)pullerApplication:Removinghubsfromsplinedortaperedaxleshaftends.wheelspanner轮胎螺丝板手Application:Looseningortighteningwheelnutsorscrews.Thosefittedwithabladeareusedtopryoffhubcaps.2.ReadingTextHandToolsandEquipmentType,QualityandSelectionAnimportantpartoftheautomotiverepairindustryisthetype,qualityandselectionofhandtoolsandequipment.Handtoolsareclassedasthosetoolswhichcanbeheldorsupportedbytheoperator’shandswhiletheyarebeingused.Equipmentisdefinedasbeingthosedeviceswhicharecontrolledbyanoperatorbutsupportedbythefloorbuildingorvehicle.ServiceandMaintenanceWhenusingalltoolsandequipment,thesafetyaspectisextremelyimportant.Toolsandequipmentusedforthepurposeforwhichtheywereintendedwillnotbearisktotheoperator,hisorherworkmatesorthecomponentpartsorthevehicle.Itistheresponsibilityoftheoperatorandtheworkshopmanagertoserviceandmaintainalltoolsandequipment.ThreeGroups:Therearethreegroupsrelatedtothetypesofhandtools.Whichincludeelectricalautomaticandmechanical?Thesegroupsare:General:---usedonawiderangeofjibs;---theyaretheresponsibilityofthetradesperson;---theirlengthislimitedtoapproximate0.5m;Specialized:---designedforaparticularjob;---theyaretheresponsibilityoftheworkshopmanager;---theirlengthmaybegreaterthan0.5m;Measuringinstruments:---theseareveryaccuratemeasuringdevice;---theyareresponsibilityofworkshopmanager.Althoughsometradespeopledosupplytheirown;---theyaregenerallyshortthan0.5m.Goodqualityhandtoolsandequipmentwillmakesurethatthejobsintheworkshopcanbecompletedwithoutdelayandtoahighstandard.Beforeanitemispurchased,caremustbetakenthatitwill:-dotherequiredjob(suitability)-lastforalongtime(durability)-operatecorrectlyeachtimeitisused(reliability)Theabilitytoquicklyselectthecorrecthandtooandorequipmenttocompleteajobsuccessfullyisachievedthroughpractice.Theaimoftoolselectionistomakereadyallthetoolsneededforthejobbeforeworkisstarted.Thisreducesthetimespent“lookingfortools”.VI:TEACHINGMETHODOLOGYAudio-visualAidsSubject-presentationwithexplanationVII:TEACHINGPROCEDUREStep1:Brieflyintroducegroupsofworkplacetoolsandequipmentwithphotosbyaudio-visualaidsorcards.Step2:IntroduceingrouptheEnglishWordsorphrasesexplaineachindetailincludingnames&types,descriptionandapplication.Step3:Checkstudents’responses.Reviewingroup.Step4:AssessthefinalcorrectionsReviewthewholecontentExplanationonTeachingProcedureVIII:ASEESSINGAPPROACHESListeningandreadingPicture/photosIdentificationIX:REFERENCEBOOKINTRODUCTIONTOMORTORMECHANICSPARTTWOWorkplaceToolsandMeasuringEquipmentUnitTwoWorkplaceMeasuringEquipmentI:UNITDESCRIPTIONThisunitidentifiesESP(word,phrasesandequipment)ofmeasuringequipment.II:NORMINALHOURS6HoursIII:TEACHINGOUTCOMEAfterteaching,studentswillbeableto:GraspESPofmeasuringequipmentDosomereadingandtranslationconcernedIV:PRIORKNOWLEDGEHigh-schoolPublicEnglishLevelV:READINGMATERIALS1.WordsandPhrasesMechanicalballgauge小空球量规Application:Usedwithanoutsidemicrometerformeasuringtheinsidediametersofsmallholesorbores.coolingsystem水温检测仪Application:Testingacoolingsystemforleaks.Testingaradiatorcappressurepressiongauge压力表Application:Testingthepressurecreatedduringthecompressionphaseinanengine.dialindicator百分表Application:Measuringsmalldistancesbetween0.01mmand10mm.forexampleabendinacrankshaft(veryaccurate)externalmicrometer外径千分尺Application:Measuringexternaldiametersorlengthsfrom0.01mmto100mm.forexamplethediameterofapistonskirt(veryaccurate)feelergauge塞尺Application:Measuringsmallclearancesorgapsthatexistbetweentwocomponents.Forexampleusedtomeasuretappetclearance.insidecaliper内卡钳Application:Usedwithasteelruleformeasuringinternaldimensionsofcomponents.Forexampletomeasuretheinsidediameterofexhausttubing.insidemicrometer内径千分尺Application:Usedwithanexternalmicrometerformeasuringtheinternaldimensionsofcomponents,forexampletomeasurethediameterofacylinderbore(veryaccurate)oilpressuregauge油压剂Application:Testingtheoilpressureofrunningengine.outsidecaliper外卡钳Application:Usedwithasteelruleformeasuringtheexternaldimensionsofcomponents.Forexampletomeasuretheoutsidediameterofexhausttubingpressureandcacuumgauge真空压力表Application:Testingthepressureandcacuumofamechanicalfuelpump.Testingtheinletmanifoldvacuumofarunningengine.sparking-pluggauge火花塞规Application:Measuringthegapthatexistsbetweentheofasparkplug,Adjustingthegapofasparkplug.steelrule钢尺Application:Measuringthedimensionsofcomponent(leastaccurateofmeasuringdevices)steeltap钢卷尺Application:Measuringdistancesthataregreaterthanonemetre.straight-edge直尺Application:Usedwithafeelergaugeformeasuringthetwistorbuckle(distortion)ofaflatsurface.tensionwrench扭钜板手Application:Settingthetensionofboltsornutstoagivenvalue.veeblockV形块Application:Usedwithaflatsurfaceforsupportingaroundorcylindricalcomponentduringameasuringtask.Forexamplecheckingacamshaftforbend.verniercaliper游标卡尺Application:Measuringdimensionsofmosttypesofshapesanddepthofholestowithin0.02mm(veryaccurate)Electricalammeter电流表Application:Measuringcurrentflowinagivenelectricalcircuit.batterydischargetester蓄电池放电检测仪Application:Testingtheconditionofabatterybyplacingitunderload.hydrometer液压表Application:Testingthespecificgravityoftheelectrolyteinvariouscellsofabattery.lowvoltagetestlight低电压表Application:Checkingtheexistenceofavoltagesupplytoanelectricalcomponent.ohmmeter电阻表Application:Testingtheresistanceofanelectricalcomponentthathasbeendisconnectedorremovedfromitscircuit.multi-meter万用表Application:Testingamps,ohmsandvoltsrelatedtothecomponentsinagivenelectricalcircuit.timinglight正时检测仪Application:Observingthetimingmarksofarunningengine.voltmeter电压表Application:Measuringthevoltagedropacrossanelectricalcomponentwhenthecircuitisturnedon.aircompressor空气压缩机Application:Pressuringandstoringairtoensureasteadysupplyata550-850kps.batterycharger充电器Application:Chargingabatteryeitherinorout.Chargingseveralbatteriesoutofthevehicles.benchgrinder台式纱轮机Application:Removingmaterialfromsmallmetalcomponents.Sharpeninghandtools.electricwelder电焊机Application:Weldingmostmetalswithanelectrodeheldinitshandpiece.2.ReadingTextAllserviceandrepairjobsrequireanalysis,diagnosis,andmeasurementtodeterminethecauseofthetrouble.Afterdisassembly,aregularseriesofstepsarerepeatedtodetermineeachcomponent’sserviceability.Toreassembleandinstallenginecomponents,makeexactmeasurementstoensureproperoperation.TYPESANDUSESIntheS.I.metricsystemofmeasurement,theunitoflengthisthemetre.Inautomotiveworkthemostcommonlyusedunitoflengthisthemillietre,whichisonethousandth(1/1000)ofameter.FormorepreciseandsmallermeasurementsthemillimeterisdividedintotenthsandhundredthsBecauseaccuratemeasurementisoftenessential,itisnecessarytolearntousethevariousmeasuringtoolsefficiently.Thesimplesttoolformeasuringisthegraduatedrulewhich,forautomotivework,ismadeofalloysteel,hardenedandground.CAREANDSTORAGEAmeasuringinstrumentisadelicateprecisioninstrumentandmustbetreatedaccordingly.Tomaintainconsistentresultsandtheaccuracyoftheinstruments,thefollowingpointsshouldbeobserved.-beforeusingtheinstrument,cleanthefaces.-checkthezerosettingbeforestartingthemeasurement.-switchoffelectricalmeterswhennotinuseandkeepthemawayfromheatandmoisture.-cleanandsteadytheworkpieceorcomponentbeingmeasuredWhentheyarenotinuse,placethembackintheirboxorplasticwallet.Storetheminasafeplace.Forexample,inacupboarddrawer,onashelforinasafeareaontheworkbenchBeforeputtingthemaway,cleantheinstrumentsandwherenecessarylightlyoilthemovingparts.Storinginstrumentsinsuchamanneraswillensurethattheyaresafefromdust,corrosionandaccidentaldamage.TYPESANDUSES---ELECTRICALTestinstrumentsManyofthecomponentoperationsonavehiclearephysical.Themethodofoperationisvisibleandcanbereadilyunderstood.Whenconsideringelectricalandelectronicsystems,theproblembecomesmoredifficult.Theeffectofelectricalcurrentisobservable–astartermotorturnsoralampisilluminated–butelectricitycannotbe‘seen’inthesamewayasitispossibletoobservetheflowofoilorfuel.Inordertotestelectricalcircuitsandcomponents,ameansofmeasuringtheflowrate(current),theflowpressure(voltage)andtheresistancetoflow(resistance)ofelectricityisrequired.Themajorityofelectricalsystemtestingcanbeachievedbytheuseofavoltmeter,anammeterandanohmmeter.Theinstrumentscanbeanalogue(movingpointeronaprintedscale)ordigital(numbersappearingonaliquidcrystaldisplay).Selectionofatestinstrumentshouldbebasedonthetypeofworkitwillbeusedtotest.Relativelycheapmovingcoilmetersareadequatewhenhighcurrentflowispresentand/orvoltagereadingaccuracyisnotcritical.Extremelyaccuratemovingcoilmetersareavailable,butthesetendtobeexpensive.Thetypeofmetergainingpopularityamongstmechanicsandtechniciansisthedigitalmulti-meter.Theseunitsarerobustandmanyareauto-ranging(eg.notnecessarytochangescalesforaccuracy).Theyareoverloadprotectedinsomerangesandcanbeswitchedtoreadamps,voltsandohms.Theaccuracyoftheseunitsonacostbasisissuperiortoanaloguemeters.Thethreeformsofelectricalcircuitsarethe1.Series2.Parallel3.Acombinationofboth,knownasseries/parallel.Aworkingknowledgeofthesecircuits,coupledwithanunderstandingofthedefinitionofthevolt,ampereandtheohmwillbeofinvaluableassistancewhenusinginstrumentsfortesting.Part1练习1NoticeChinaInternationalTenderingCompanyChinaNationalTechnicalImport&ExportCorporationHunanXiangjiangNavigationConstruction&DevelopmentCorporationLtdInlandWaterwayProjectCivil