已阅读5页,还剩7页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
英文译文tapetransportAmongthemethodsofmaterialconveyingquantity,beltconveyorsplayaveryimportantpartinthereliablecarryingofmaterialoverlongdistancesatcompetitivecost.Conveyorsystemshavebecomelargerandmorecomplexanddrivesystemshavealsobeengoingthroughaprocessofevolutionandwillcontinuetodoso.Nowadays,biggerbeltsrequiremorepowerandhavebroughttheneedforlargerindividualdrivesaswellasmultipledrivessuchas3drivesof750kWforonebelt(thisisthecasefortheconveyordrivesinChengzhuangMine).Theabilitytocontroldriveaccelerationtorqueiscriticaltobeltconveyorsperformance.Aefficientdrivesystemshouldbeabletoprovidesmooth,softstartswhilemaintainingbelttensionswithinthespecifiedsafelimits.Forloadsharingonmultipledrives.torqueandspeedcontrolarealsoconsiderationsinthedrivesystemsdesign.Duetotheadvancesinconveyordrivecontroltechnology,atpresentmanymorereliable.Cost-effectiveandperformance-drivenconveyordrivesystemscoveringawiderangeofpowerareavailableforcustomerschoices1.1tapetransportonconveyordrivetechnologies1.1ThebelttransmissionmodeFull-voltagestarters.Withafull-voltagestarterdesign,theconveyorheadshaftisdirect-coupledtothemotorthroughthegeardrive.Directfull-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.WoundrotorinductionmotorsareconnecteddirectlytothedrivesystemreducerandareamodifiedconfigurationofastandardACinductionmotor.Byinsertingresistanceinserieswiththemotorsrotorwindings.themodifiedmotorcontrolSystemcontrolsmotortorque.Forconveyorstarting,resistanceisplacedinserieswiththerotorforlowinitialtorque.Astheconveyoraccelerates,theresistanceisreducedslowlytomaintainaconstantaccelerationtorque.Onmultiple-drivesystems.anexternalslipresistormaybeleftinserieswiththerotorwindingstoaidinloadsharing.themotorsystemshavearelativelysimpleadesign.However,thecontrolsystemsforthesecanbehighlycomplex,becausetheyarebasedoncomputercontroloftheresistanceswitching.Today,themajorityofcontrolsystemsarecustomdesignedtomeetaconveyorsystemsparticularspecifications.Woundrotormotorsareappropriateforsystemsrequiringmorethan400KW.DCmotor.DCmotors.availablefromafractionofthousandsofKW,aredesignedtodeliverconstanttorquebelowbasespeedandconstantKWabovebasespeedtothemaximumallowablerevolutionsperminute(r/min).withthemajorityofconveyordrives,a.DCshuntwoundmotorisused.Whereinthemotorsrotatingarmatureisconnectedexternally.ThemostcommontechnologyforcontrollingDCdrivesisaSCRdevice.whichallowsforcontinualvariable-speedoperation.TheDCdrivesystemismechanicallysimple,butcanincludecomplexcustom-designedelectronicstomonitorandcontrolthecompletesystem.thissystemoptionisexpensiveincomparisontoothersoft-startsystems.butitisareliable,cost-effectivedriveinapplicationsinwhichtorque,loadsharingandvariablespeedareprimaryconsiderations.DCmotorsgenerallyareusedwithhigher-powerconveyors,includingcomplexprofileconveyorswithmultiple-drivesystems,boostertrippersystemsneedingbelttensioncontrolandconveyorsrequiringawidevariable-speedrange.1.2HydrokineticcouplingHydrokineticcouplings,commonlyreferredtoasfluidcouplings.arecomposedofthreebasicelements;thedrivenimpeller,whichactsasacentrifugalpump;thedrivinghydraulicturbineknownastherunnerandacasingthatenclosesthetwopowercomponents.Hydraulicfluidispumpedfromthedrivenimpellertothedrivingrunner,producingtorqueatthedrivenshaft.Becausecirculatinghydraulicfluidproducesthetorqueandspeed,nomechanicalconnectionisrequiredbetweenthedrivinganddrivershafts.Thepowerproducedbythiscouplingisbasedonthecirculatedfluidsamountanddensityandthetorqueinproportiontoinputspeed.Becausethepumpingactionwithinthefluidcouplingdependsoncentrifugalforces.theoutputspeedislessthantheinputspeed.Referredtoasslip.thisnormallyisbetween1%and3%.BasichydrokineticcouplingsareavailableinconfigurationsfromfractionaltoseveralthousandKW.Fixed-fillfluidcouplings.Fixed-fillfluidcouplingsarethemostcommonlyusedsoft-startdevicesforconveyorswithsimplerbeltprofilesandlimitedconvex/concavesections.Theyarerelativelysimple,low-cost,reliable,maintenancefreedevicesthatprovideexcellentsoftstartingresultstothemajorityofbeltconveyorsinusetoday.Variable-filldraincouplings.Drainable-fluidcouplingsworkonthesameprincipleasfixed-fillcouplings.ThecouplingsimpellersaremountedontheACmotorandtherunnersonthedrivenreducerhigh-speedshaft.Housingmountedtothedrivebaseenclosestheworkingcircuit.Thecouplingsrotatingcasingcontainsbleed-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.VFCdevicesProvidevariablefrequencyandvoltagetotheinduc
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 2024年3月春季中国工商银行安徽省分行校园招考聘用360人笔试参考题库附带答案详解
- 2024年3月中国工商银行平台金融发展中心春季校园招考聘用30人笔试参考题库附带答案详解
- 2024年04月江苏省生态环境厅机关服务中心招考聘用编外劳务派遣工作人员笔试参考题库附带答案详解
- 2024年03月湖南省张家界市武陵源区总工会2024年招考1名社会化工作者笔试参考题库附带答案详解
- 2024年03月浙江省台州湾新区2024年招考笔试参考题库附带答案详解
- 2024年03月江苏省盐城市退役军人事务局2024年公开招录1名政府购买服务用工笔试参考题库附带答案详解
- 2024年03月广东省佛冈县妇女联合会2024年公开招考1名专项聘员笔试参考题库附带答案详解
- 2024年03月宁夏回族自治区总工会2024年公开招考88名社会化工会工作者笔试参考题库附带答案详解
- 2024年上海住院医师-上海住院医师康复医学科笔试参考题库含答案
- 美发师:高级美发师考试题库(强化练习)
- GB/T 26559-2011机械式停车设备分类
- 2022年健康洞察疼痛系列报告-痛风篇20221022
- 现浇混凝土构件尺寸检测记录
- 检验科应急预案制度流程汇编
- 白内障超声乳化手术配合课件
- 职场礼仪之微信沟通礼仪课件
- 室内燃气管道安装施工
- 广告设计概论课件
- 1972-保护世界文化和自然遗产公约
- 2022年9月29日江西省烟草局面试真题及答案解析
- 毕业论文-基于Silvaco TCAD半浮栅晶体管的3D建模
评论
0/150
提交评论