中英文中英文文献翻译带传动设计.docx
- 文档编号:8145805
- 上传时间:2023-01-29
- 格式:DOCX
- 页数:8
- 大小:25.17KB
中英文中英文文献翻译带传动设计.docx
《中英文中英文文献翻译带传动设计.docx》由会员分享,可在线阅读,更多相关《中英文中英文文献翻译带传动设计.docx(8页珍藏版)》请在冰豆网上搜索。
中英文中英文文献翻译带传动设计
英文译文
tapetransport
Amongthemethodsofmaterialconveyingquantity,beltconveyorsplayaveryimportantpartinthereliablecarryingofmaterialoverlongdistancesatcompetitivecost.Conveyorsystemshavebecomelargerandmorecomplexanddrivesystemshavealsobeengoingthroughaprocessofevolutionandwillcontinuetodoso.Nowadays,biggerbeltsrequiremorepowerandhavebroughttheneedforlargerindividualdrivesaswellasmultipledrivessuchas3drivesof750kWforonebelt(thisisthecasefortheconveyordrivesinChengzhuangMine).Theabilitytocontroldriveaccelerationtorqueiscriticaltobeltconveyors'performance.Aefficientdrivesystemshouldbeabletoprovidesmooth,softstartswhilemaintainingbelttensionswithinthespecifiedsafelimits.Forloadsharingonmultipledrives.torqueandspeedcontrolarealsoconsiderationsinthedrivesystem'sdesign.Duetotheadvancesinconveyordrivecontroltechnology,atpresentmanymorereliable.Cost-effectiveandperformance-drivenconveyordrivesystemscoveringawiderangeofpowerareavailableforcustomers'choices[1].
1tapetransportonconveyordrivetechnologies
1.1Thebelttransmissionmode
Full-voltagestarters.Withafull-voltagestarterdesign,theconveyor
headshaftisdirect-coupledtothemotorthroughthegeardrive.Direct
full-voltagestartersareadequateforrelativelylow-power,simple-Profileconveyors.Withdirectfull-voltagestarters.nocontrolisprovidedforvariousconveyorloadsand.dependingontheratiobetweenfull-andno-loadpowerrequirements,emptystartingtimescanbethreeorfourtimesfasterthanfullload.Themaintenance-freestartingsystemissimple,low-costandveryreliable.However,theycannotcontrolstartingtorqueandmaximumstalltorque;therefore.theyarelimitedtothelow-power,simple-profileconveyorbeltdrives.
Reduced-voltagestarters.Asconveyorpowerrequirementsincrease,controllingtheappliedmotortorqueduringtheaccelerationperiodbecomesincreasinglyimportant.Becausemotortorqueisafunctionofvoltage,motorvoltagemustbecontrolled.Thiscanbeachievedthroughreduced-voltagestartersbyemployingasiliconcontrolledrectifier(SCR).AcommonstartingmethodwithSCRreduced-voltagestartersistoapplylowvoltageinitiallytotakeupconveyorbeltslack.andthentoapplyatimedlinearrampuptofullvoltageandbeltspeed.However,thisstartingmethodwillnotproduceconstantconveyorbeltacceleration.Whenaccelerationiscomplete.theSCRs,whichcontroltheappliedvoltagetotheelectricmotor.arelockedinfullconduction,providingfull-linevoltagetothemotor.Motorswithhighertorqueandpull-vptorque,canprovidebetterstartingtorquewhencombinedwiththeSCRstarters,whichareavailableinsizesupto750KW.
Woundrotorinductionmotors.Woundrotorinductionmotorsare
connecteddirectlytothedrivesystemreducerandareamodifiedconfigurationofastandardACinductionmotor.Byinsertingresistanceinserieswiththemotor'srotorwindings.themodifiedmotorcontrolSystemcontrolsmotortorque.Forconveyorstarting,resistanceisplacedinserieswiththerotorforlowinitialtorque.Astheconveyoraccelerates,theresistanceisreducedslowlytomaintainaconstantaccelerationtorque.Onmultiple-drivesystems.anexternalslipresistormaybeleftinserieswiththerotorwindingstoaidinloadsharing.themotorsystemshavearelativelysimpleadesign.However,thecontrolsystemsforthesecanbehighlycomplex,becausetheyarebasedoncomputercontroloftheresistanceswitching.Today,themajorityofcontrolsystemsarecustomdesignedtomeetaconveyorsystem'sparticularspecifications.Woundrotormotorsareappropriateforsystemsrequiringmorethan400KW.
DCmotor.DCmotors.availablefromafractionofthousandsofKW,aredesignedtodeliverconstanttorquebelowbasespeedandconstantKWabovebasespeedtothemaximumallowablerevolutionsperminute(r/min).withthemajorityofconveyordrives,a.DCshuntwoundmotorisused.Whereinthemotor'srotatingarmatureisconnectedexternally.ThemostcommontechnologyforcontrollingDCdrivesisaSCRdevice.whichallowsforcontinualvariable-speedoperation.TheDCdrivesystemismechanicallysimple,butcanincludecomplexcustom-designedelectronicstomonitorandcontrolthecompletesystem.thissystemoptionisexpensiveincomparisontoothersoft-startsystems.butitisareliable,cost-effectivedriveinapplicationsinwhichtorque,loadsharingandvariablespeedareprimaryconsiderations.DCmotorsgenerallyareusedwithhigher-powerconveyors,includingcomplexprofileconveyorswithmultiple-drivesystems,boostertrippersystemsneedingbelttensioncontrolandconveyorsrequiringawidevariable-speedrange.
1.2Hydrokineticcoupling
Hydrokineticcouplings,commonlyreferredtoasfluidcouplings.arecomposedofthreebasicelements;thedrivenimpeller,whichactsasa
centrifugalpump;thedrivinghydraulicturbineknownastherunnerand
acasingthatenclosesthetwopowercomponents.Hydraulicfluidispumpedfromthedrivenimpellertothedrivingrunner,producingtorqueatthedrivenshaft.Becausecirculatinghydraulicfluidproducesthetorqueandspeed,nomechanicalconnectionisrequiredbetweenthedrivinganddrivershafts.Thepowerproducedbythiscouplingisbasedonthecirculatedfluid'samountanddensityandthetorqueinproportiontoinputspeed.Becausethepumpingactionwithinthefluidcouplingdependsoncentrifugalforces.theoutputspeedislessthantheinputspeed.Referredtoasslip.thisnormallyisbetween1%and3%.BasichydrokineticcouplingsareavailableinconfigurationsfromfractionaltoseveralthousandKW.
Fixed-fillfluidcouplings.Fixed-fillfluidcouplingsarethemostcommonlyusedsoft-startdevicesforconveyorswithsimplerbeltprofilesandlimitedconvex/concavesections.Theyarerelativelysimple,low-cost,reliable,maintenancefreedevicesthatprovideexcellentsoftstartingresultstothemajorityofbeltconveyorsinusetoday.
Variable-filldraincouplings.Drainable-fluidcouplingsworkonthesameprincipleasfixed-fillcouplings.Thecoupling'simpellersaremountedontheACmotorandtherunnersonthedrivenreducerhigh-speedshaft.Housingmountedtothedrivebaseenclosestheworkingcircuit.Thecoupling'srotatingcasingcontainsbleed-offorificesthatcontinuallyallowfluidtoexittheworkingcircuitintoaseparatehydraulicreservoir.Oilfromthereservoirispumpedthroughaheatexchangertoasolenoid-operatedhydraulicvalvethatcontrolsthefillingofthefluidcoupling.Tocontrolthestartingtorqueofasingle-driveconveyorsystem,theACmotorcurrentmustbemonitoredtoprovidefeedbacktothesolenoidcontrolvalve.Variablefilldraincouplingsareusedinmediumtohigh-kwconveyorsystemsandareavailableinsizesuptothousandsofkw.Thedrivescanbemechanicallycomplexanddependingonthecontrolparameters.thesystemcanbeelectronicallyintricate.Thedrivesystemcostismediumtohigh,dependinguponsizespecified.
Hydrokineticscoopcontroldrive.Thescoopcontrolfluidcouplingconsistsofthethreestandardfluidcouplingcomponents:
adrivenimpeller,adrivingrunnerandacasingthatenclosestheworkingcircuit.Thecasingisfittedwithfixedorificesthatbleedapredeterminedamountoffluidintoareservoir.Whenthescooptubeisfullyextendedintothereservoir,thecouplingis100percentfilled.Thescooptube,extendingoutsidethefluidcoupling,ispositionedusinganelectricactuatortoengagethetubefromthefullyretractedtothefullyengagedposition.Thiscontrolprovidesreasonablysmoothaccelerationrates.tobutthecomputer-basedcontrolsystemisverycomplex.Scoopcontrolcouplingsareappliedonconveyorsrequiringsingleormultipledrivesfrom150KWto750KW.
1.3Variable-frequencycontrol(VFC)
Variablefrequencycontrolisalsooneofthedirectdrivemethods.theemphasizingdiscussionaboutithereisbecausethatithassouniquecharacteristicandsogoodperformancecomparedwithotherdrivingmethodsforbeltconveyor.VFCdevicesProvidevariablefrequencyandvoltagetotheinductionmotor,resultinginanexcellentstartingtorqueandaccelerationrateforbeltconveyordrives.VFCdrives.availablefromfractionaltoseveralthousand(kW),areelectroniccontrollersthatrectifyAClinepowertoDCand,throughaninverter,convertDCbacktoACwithfrequencyandvoltagecontrol.VFCdrivesadoptvectorcontrolordirecttorquecontrol(DTC)technology,andcanadoptdifferentoperatingspeedsaccordingtodifferentloads.VFCdrivescanmakestartingorstallingaccordingtoanygivenS-curvesrealizingtheautomatictrackforstartingorstallingcurves.VFCdrivesprovideexcellentspeedandtorquecontrolforstartingconveyorbelts.andcanalsobedesignedtoprovideloadsharingformultipledrives.easilyVFCcontrollersarefrequentlyinstalledonlower-poweredconvey-ordrives,butwhenusedattherangeofmedium-highvoltageinthepast.thestructureofVFCcontrollersbecomesverycomplicatedduetothelimitationofvoltageratingofpowersemiconductordevices,thecombinationofmedium-highvoltagedrivesandvariablespeedisoftensolvedwithlow-voltageinvertersusingstep-uptransformerattheoutput,orwithmultiplelow-voltageinvertersconnectedinseries.Three-levelvoltage-fedPWMconvertersystemsarerecentlyshowingincreasingpopularityformulti-megawattindustrialdriveapplicationsbecauseofeasyvoltagesharingbetweentheseriesdevicesandi叩rovedharmonicqualityattheoutputcomparedtotwo-levelconvertersystemsWithsimple
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 中英文 文献 翻译 传动 设计
![提示](https://static.bdocx.com/images/bang_tan.gif)