机械毕业设计英文外文翻译324煤矿业带式输送机几种软起动方式的比较

1、A Comparis on of Soft Start Mecha ni sms for Mi ning BeltCon veyors煤矿业带式输送机几种软起动方式的比较（中英文对照）网自空 el L. Nave, P.E.统一公司1800年华盛顿路匹兹堡,PA 15241带式运送机是采矿工业运输大 批原料的重要方法。从传送带驱动系统到传送带纹理结构启动力矩的应 用和控制影响着运送机的性能，寿命和可靠性。本文考查了不同启动方 法在煤矿工业带式运送机中的应用。简介运行带式运送机的动力必须由驱动滑轮产生，通过滑轮和传送带之 间的摩擦力来传递。为了传递能量，传送带上面的张力在接近滑轮部分 和离开滑轮

2、部分必定存在着差别。这种差别在稳定运行、启动和停止时 刻都是真实存在的。传统传送带结构的设计，都是根据稳定运行情况下 传送带的受力情况。因为设计过程中没有详尽研究传送带启动和停止阶 段的受力情况，所有的安全措施都集中在稳定运行阶段（Harriso n1987）。本文主要集中讲述传送机启动和加速阶段的特性。传送带设计 者在设计时必须考虑控制启动阶段的加速状况，以免使传送带和传送机 驱动系统产生过大的张力和动力（Suttees，1986）。大加速度产生的 动力会给传送带的纹理、传送带结合处、驱动滑轮、轴承、减速器以及 耦合器带来负面影响。毫无控制的加速度产生的动力能够引起带式传送 机系统产生诸多不

3、良问题，比如上下曲线运动、过度传送带提升运动、 滑轮和传送带打滑、运输原料的溢出和传送带结构。传送带的设计需要 面对两个问题：第一，传送带驱动系统必须能够产生启动带式传送机的 最小转动力矩；第二，控制加速度产生动力在安全界限内。可以通过驱 动力矩控制设备来完成，控制设备可以是电子手段也可以是机械手段， 也可以是两者的组合（CEM 1979）。本文主要阐述输送机的开始和加速的过程。 传送带设计师必须控制 开始加速度防止过度张紧在传送带织品和力量在皮带传动系统强加速度力量可能有害地影响传送带织品，传送带接合，驱动皮带轮，更加 无所事事的滑轮，轴，轴承，速度还原剂，并且联结。未管制的加速度 力量可能

4、造成皮带输送机有垂直的曲线的系统性能问题，传送带紧线器 运动，驱动皮带轮摩擦损失，材料溢出，并且做成花彩传送带织品。传 送带设计员与二个问题被面对，皮带传动系统必须导致极小的扭矩足 够强有力开始传动机，和控制了这样加速度强制是在安全限额内。光滑 开始传动机可能由对驱动器扭矩控制设备的用途，或机械或电子，或 组合的二完成(CEM 1979)。软起动结构评估标准什么是最佳的皮带输送机驱动系统？答案取决于许多变量。最佳的系统 是一个为开始，运行，和终止提供可接受的控制在合理的费用和以及 高可靠性。皮带传动系统为本文我们考虑的设计方案，皮带输送机被电 子头等搬家工人几乎总驱动。传送带驱动系统将包括多个

5、要素包括 电子原动力、电子马达起始者以控制系统，马达联结、速度还原剂、低 速联结、皮带传动滑轮、和滑轮闸(Cur 1986)。它重要,传送带设计 员审查各个系统要素的适用性对特殊申请。为本文的目的，我们假设，所有驱动系统要素设置矿的新鲜空气 ，非允许，面积,全国电子编码， 条款500防爆，矿的表面的面积。皮带传动要素归因于范围。某些驱 动器要素是可利用和实用的用不同的范围。 为这论述，我们假设那皮带 传动系统范围从分数马力对千位的多个马力。小驱动系统经常是在50马力以下。中型系统范围从 50到1000马力。大型系统可能被考虑在 1000马力之上。范围分部入这些组是整个地任意的。必须被保重抵抗

6、诱惑对超出马达或在马达之下传送带飞行提高标准化。驱动器结果在粗劣的效率和在高扭矩的潜在，当驱动器能导致破坏性超速在再生，或 过度加热以变短的马达寿命。扭矩控制。传送带设计员设法限制开始的 扭矩到没有比150%运行中。限额在应用的开始的扭矩经常是传送带胴体肉、传送带接合、滑轮绝热材料，轴偏折评级。在更大的传送带和传 送带以优化大小的要素,扭矩限额110%至125%是公用。除扭矩限额 之外，传送带起始者必需限制会舒展围绕和会导致旅行的波浪的扭矩 增量。一个理想的开始的控制系统会适用于资格整个传送带的扭矩传送 带休息由问题的脱离决定，或运动，然后扭矩相等与传送带的运动需 求以负荷加上恒定的扭矩从休息

7、加速系统要素的惯性对最终奔跑速度。 这使系统临时强制和传送带舒展。不同的驱动系统陈列变化的能力控制 扭矩的申请对传送带休息和以不同的速度。并且，传动机陈列装载二个 极端。一条空传送带正常存在最小的必需的扭矩为脱离和加速度，当一 条充分地被装载的传送带存在最高的必需的扭矩。开采驱动系统必须是 能称应用的扭矩从一个 2/1比率为一个水平的简单传送带安排，对一 个10/1范围为一个倾斜、复杂传送带配置文件。热量评级在开始和运行期间，各个驱动系统也许消散废热。废热也许被解放 在电子马达、电子控制、，联结、速度还原剂，或传送带制动系统。各 个起始时间热量负荷依靠相当数量传送带负荷和起始时间的期限。设计员

8、必须履行被重复的起始时间的申请需求在运行传动机以后在全负荷。 典型的开采传送带开始的责任变化从 3到10个起始时间每时数等隔， 或2到4个起始时间在连续。被重复的开始也许要求减税或系统要素。 有一个直接关系在热量评级为被重复的起始时间和费用之间。可变速 度。一些皮带传动系统是适当的为控制开始的扭矩和速度，但只运行以 恒定的速度。一些传送带申请会要求一个驱动系统能运行延长的期间以 较不比最高速度。这是有用的当驱动器负荷必须与其它驱动器被共享，传送带被使用当处理饲养者为被表达的物料的费率控制，传送带速度 被优选为货车使用费费率，传送带被使用以慢速运输人工或材料，或传 送带运行缓慢的检验或移动速度为

9、维护目的。 可变速度皮带传动将要求 一个控制系统根据某一算法调控操作速度。再生或翻修负荷。一些传送带配置文件存在翻修传送带系统用品能量对驱动系统的负荷的潜在。没有所有驱动系统有能力接受被重新生成的能量从负荷。一些驱动器可能 接受能量从负荷和退回它到输电线供其它负荷使用。其它驱动器接受能 量从负荷和消散它入选定的动态或机械刹车的要素。一些传送带描出切换从开汽车对再生在运算期间。驱动系统可能接受有些巨大的被重新生 成的能量为申请吗？驱动系统控制或必须调整相当数量减速的强制在 翻修期间吗？翻修发生当运行和开始？维护和支持系统。各个驱动系统 将要求定期预防维护。可替换的项目会包括马达画笔、轴承、闸填充

10、、 散逸电阻器、油，和凉水。如果驱动系统被设计和保守地被管理，更低 的重音在可消耗导致更低的维修费用。一些驱动器要求支持系统譬如流 通的油为润滑油、冷却空气或水，环境尘土过滤，或计算机仪器工作。 支持系统的维护可能影响驱动系统的可靠性。费用驱动器设计员将审查各个驱动系统的费用。费用合计是第一基建成 本获取驱动器，费用安装和委任驱动器，费用运行驱动器，和费用的 总和维护驱动器。费用使力量运行驱动器也许广泛变化用不同的地点。 设计员努力符合所有系统性能要求在最低的费用合计。经常超过一个驱 动系统也许满足所有系统性能标准在竞争费用。更喜欢的驱动器安排是 最简单，譬如一个唯一马达驱动通过一个唯一顶头滑

11、轮。但是 ，机械, 经济，和功能需求经常需要对复杂驱动器的用途。传送带设计员必须平 衡对优雅的需要反对伴随复杂系统的问题。复杂系统要求额外设计工程 为成功配置。经常被忽略的费用在复杂系统是培训人事部的费用 ，或停 工期的费用由于不足的培训。软起动驱动控制逻辑各个驱动系统将要求一个控制系统调控开始的机制。 最共同的类型控制 被使用在更小对中等大小驱动以简单的外形被命名 开环加速度控制 0在开环，控制系统早先被配置程序化开始的机制以被规定的方式 ， 通常准时根据。 在开环控制，驾驶使用参数譬如潮流，扭矩，或速度不影响序列操作。这个方法假定，控制设计师充分地塑造了驱动系统 表现在传动机。 为更大或更

12、加复杂的传送带，闭合回路或反馈 控制可以他运用了。 在闭合回路控制，在开始期间，控制系统显示器 通过传感器驾驶使用参数譬如马达的当前层，传送带的速度，或力量在传送带，并且修改起动程序控制，极限，或优选或佩带了参量。闭合 回路控制系统修改开始的被应用的力量在一台空和充分地被装载的传 动机之间。常数在数学模型与被测量的可变物有关对系统驱动反应被命 名定调的常数。 这些常数必须适当地被调整为成功的应用对各台传动 机。最共同的计划为传动机开始闭合回路控制是车头表反馈为速度控 制和压电池力量或驱动力反馈为扭矩控制。 在一些复杂系统，它是中意 安排闭合回路控制系统调整自己为各种各样的遇到的传动机情况。这被

13、命名能适应的控制。这些极端可能介入浩大的变异在装货，围绕 的温度，装货的地点在外形，或多个驱动选择在传动机。有三个共同的能适应的方法。介入决定做在开始之前，如果控制系统能知道传送带 是空的，它会减少最初的力量和会加长加速度力量的应用对最高速度。 如果传送带被装载，控制系统会应用资格力量在摊位之下使较少时刻 和供应充足的扭矩及时地充分地加速传送带。因为传送带只成为了装载在早先赛跑期间由装载驱动，平均驱动潮流可能被抽样当连续和被 保留在反射传送带搬运器时间的缓冲记忆。 然后在停工平均也许是预先 处理一些开环和闭合回路为下个开始。 第二个方法介入根据驱动观察发 生在最初开始或行动期间证明的决定。这及

14、时驱动潮流的或力量通 常介入比较对传送带速度。如果驱动潮流或力量必需及早在序列是降 低并且行动被创始，传送带必须被卸载。如果驱动潮流或力量必需是高 的。在开始，传动机必须被装载。 这个决定可能被划分在区域和使用 修改起动程序控制的中部和结束。第三个方法介入传送带速度的比较对 时刻为这个开始反对传送带加速度历史极限，或加速度信封监视。在开始，传送带速度被测量对时间。这与被保留在控制系统记忆的 二限制的传送带速度曲线比较。第一曲线描出空的传送带加速，并且第 二个充分地被装载的传送带。因而，如果当前的速度对时间比被装载的外形低，它也许表明，传送带被超载，妨碍，或驱动故障。 如果当前的速度对时间比空间

15、的外形高级，它也许表明一条残破的传送带结 合或驱动故障。无论如何，当前的起飞中止并且警报运行。结论最好的传送带启动系统要求在不同的传送带负载条件下，能够以合理的代价带来可靠性高的可以接受的运行性能。 但是至今没有一个启动 系统能够达到这样的要求。传送带设计者必须为每个传送带设计启动系 统属性。总得来说，全电压交流发动机启动适合于简单结构的小型传送 带。减电压SCR交流发动机启动是地下中、小型传送带的基本启动方法。 最新的进展显示，固定液体填充耦合系统的交流发动机是简单结构中、 大型传送带基本启动方法。对于那些大、中型而且需要重复启动的复杂 结构传送带，绕线转子发动机驱动是常用的选择。在结构特别

16、复杂，运 行需要不同速度的传送带启动中， 传送带直流发动机驱动、不同填充液 体驱动、和相异机械传递驱动系统一直实力相当的候选者。具体选择哪 个启动方式由使用环境，相对价格，运行能耗，反应速度和使用者习惯 来决定。变频交流驱动和非电刷直流驱动主要限制于中型传送带，这些中型传送带需要精确的速度控制，高代价和复杂性。但是，随着持续的 竞争和技术进步，波形综合技术的电子驱动器的使用将越来越广。A Comparis on of Soft Start Mecha ni sms for Mining BeltConv eyorsMichael L. Nave, P.E.CONSOL Inc.1800 Was

17、hington Road Pittsburgh,PA 15241 Belt Conveyors arean importa nt method for tran sportatio n of bulk materials in the mining industry. The control of the application of the starting torque from the belt drive system to the belt fabric affects the performanee, life cost, and reliability of the convey

18、or. This paper exam ines applicati ons of each start ing method withi n the coal mining in dustry.INTRODUCTIONThe force required to movea belt conveyor must be transmitted by the drive pulley via frictionbetween the drive pulley and thebelt fabric.In order to transmit power there must be a differene

19、ein the belt tension as it approaches and leaves the drive pulley. These conditions are true for steady state running, starting,andstopp ing. Traditi on ally, belt desig ns are based on static calculati ons of running forces. Since start ing and stopp ing are not examined in detail, safety factors a

20、re applied to static loadings (Harrison, 1987). This paper will primarily address the startingor accelerationduty of the conveyor. The belt designermust con trol start ing accelerati on to preve nt excessive tension in the belt fabric and forces in the belt drive system (Suttees, 1986). High acceler

21、atio n forces can adversely affect the belt fabric, belt splices, drive pulleys, idler pulleys, shafts, beari ngs, speed reducers, and coupli ngs. Uncon trolled accelerati on forces can cause belt conv eyor system performa nee problems with vertical curves, excessive belt take-up moveme nt,loss of d

22、rive pulley frict ion, spillage of materials, andfestooning of the belt fabric. The belt designer is confronted with two problems, The belt drive system must produce a minimum torque powerful eno ugh to start the con veyor, and con trolled such that the accelerati on forces are within safe limits. S

23、mooth start ing of the conv eyor can be accomplished by the use of drive torque con trol equipme nt, either mecha ni cal or electrical, or a comb in ati on of the two (CEM, 1979).SOFT START MECHANISM EVALUATION CRITERIONWhat is the best belt conv eyor drive system? The an swer depe nds on many varia

24、bles. The best system is one that provides acceptable con trol for start ing, running, and stopp ing at a reas on able cost and with high reliability (Lewdly and Sugarca ne, 1978). BeltDrive System For the purposes of this paper we will assume that belt conveyors are almost always driven by electric

25、al prime movers (Goodyear Tire and Rubber, 1982). The belt drive system shall con sist of multiple comp onents in cludi ng the electrical prime mover, the electrical motor starter with con trol system, the motor coupli ng, the speed reducer, the low speed coupli ng, the belt drive pulley, and the pu

26、lley brake or hold back (Cur,1986). It is important that the belt designer examine the applicability of each system component to the particular application. For the purpose of this paper, we will assume that all drivesystem components are located in the fresh air,non-permissible, areas of the mine,

27、or in non-hazardous, National Electrical Code, Article 500 explosion-proof,areas of thesurface of the mine.Belt Drive Comp onent Attributes Size.Certa in drive comp onents are available and practical in differe nt size ran ges. For this discussi on, we will assume that belt drive systems range from

28、fractional horsepower to multiples of thousa nds of horsepower. Small drive systems are ofte n below 50 horsepower. Medium systems range from 50 to 1000 horsepower. Large systems can be con sidered above 1000 horsepower. Divisi on of sizes into these groups is en tirely arbitrary. Care must be taken

29、 to resist the temptation to over motor or under motor a belt flight to enhance standardization.An over motored drive resultsin poor efficie ncy and the pote ntial for high torques, while an un der motored drive could result in destructive overspe nding on rege nerati on, or overheat ing with shorte

30、 ned motor life (Lords, et al., 1978).Torque Con trol.Belt designers try to limit the starting torque to no more than 150%of the running torque (CEMA, 1979; Goodyear, 1982). The limit on the applied start ing torque is ofte n the limit of rati ng of the belt carcass, belt splice, pulley lagging, or

31、shaft deflect ions. On larger belts and belts with optimized sized comp onen ts, torque limits of 110% through 125% are com mon (Elberton,1986). In addition to a torque limit, the belt startermay be required to limit torque in creme nts that would stretch belt ing and cause traveli ng waves. An idea

32、l start ing con trol system would apply a prete nsion torque to the belt at rest up to the point of breakaway, or moveme nt of the en tire belt, the n a torque equal to the movement requirements of the belt with load plus a con sta nt torque to accelerate the in ertia of the system components from r

33、est to final running speed. This would minimizesystem tran sie nt forces and belt stretch (Shultz, 1992).Differe nt drive systems exhibit vary ing ability to con trol the applicationof torques to the belt at rest and at differentspeeds.Also, the conv eyor itself exhibits two extremes of load ing. An

34、 empty belt n ormally prese nts the smallest required torque for breakaway and accelerati on, while a fully loaded belt prese nts the highest required torque. A mining drive system must be capable of scaling the applied torque from a 2/1 ratio for a horizontal simple belt arran geme nt, to a 10/1 ra

35、n ges for an in cli ned or complex belt profile.Thermal Rati ng.During start ing and running, each drive system may dissipate waste heat. The waste heat may be liberated in the electrical motor, the electricalcontrols,the couplings, the speed reducer,or the belt brak ing system. The thermal load of

36、each start Is dependent on the amount of belt load and the duration of the start. The designer must fulfill the applicationrequirementsforrepeated starts after running the conveyor at full load. Typical mining belt ELIEEIstarting duties vary from 3 to 10 starts per hour equally spaced, or 2 to 4 sta

37、rts in succession. Repeated starting may require the dread ing or over siz ing of system comp onen ts.There is a directrelati on shipbetwee n thermalrat ingforrepeated starts and costs. Variable Speed. Some belt drive systems are suitable for con trolli ng the starti ng torque and speed, but only ru

38、n at con sta nt speed. Some belt applicati ons would require a drive system capable of running for exte nded periods at less tha n full speed. This is useful whe n the drive load must be shared with other drives, the belt is used as aprocess feeder for rate control of the conveyed material,the belts

39、peed is optimized for the haulage rate, the belt is used at slower speeds to tran sport men or materials, or the belt is run a slow in spect ion or inching speed for maintenance purposes (Hager, 1991). The variable speed belt drive will require a control system based on somealgorithm to regulate ope

40、rating speed. Regeneration or Overhauling Load. Somebelt profilespresent the potentialforoverhauli ng loads where the belt system supplies en ergy to the drive system. Not all drive systems have the ability to accept rege nerated en ergy from the load. Some drives can accept en ergy from the load an

41、d return it to the power line for use by other loads. Other drives accept energy from the load and dissipate it into designated dynamic or mechanical braking elements. Somebelt profiles switch from motori ng to rege neratio n duri ng operati on.Can the drive system accept regenerated energy of a cer

42、tain magn itude for the applicati on? Does the drive system have to control or modulate the amount of retarding force during overhauling? Does the overhauling occur whenrunning and starting? Maintenance and SupportingSystems. Each drive system willrequire periodicpreve ntativemaintenan ce. Replaceab

43、le itemswould in clude motor brushes, beari ngs, brake pads, dissipati on resistors, oils,and cooling water. If the drive system isconservativelyengineered and operated, the lower stress oncon sumables will result in lower maintenance costs. Some drives require support ing systems such as circulat i

44、ng oil for lubrication,cooling air or water, environmental dust filtering,or computer in strume ntatio n. The maintenance of the support ing systems can affect the reliability of the drive system.Cost.The drive designer will examine the cost of each drive system. The total cost is the sum of the fir

45、st capital cost to acquire the drive, the cost to in stall and commissi on the drive, the cost to operate the drive, and the cost to maintain the drive. The cost for power to operate the drive may vary widely with differe nt locati ons. The desig ner strives to meet all system performa nee requireme

46、 nts at lowest total cost. Ofte n more tha n one drive system may satisfy all system performa nee criteri ons at competitive costs.Complexity.The preferred drive arrangement is the simplest, such as a single motor driving through 13 3 a singlehead pulley. However,mecha ni cal,econo mic, and function

47、al requireme ntsofte nn ecessitate the use of complex drives. The belt desig ner must bala nee the n eed for sophisticati on aga inst the problems that accompa ny complex systems. Complex systems require additi onal desig nengin eeri ngfor successful deployme nt. Anoften-overlooked cost in a complex

48、 system is the cost of training on site pers onn el,or the cost of dow ntime as a result ofin sufficie nt training.SOFT START DRIVE CONTROL LOGICEach drive system will require a con trol system to regulate the starti ngmecha ni sm. The most com mon type of con trolused onsmaller to medium sized driv

49、es with simple profiles is termedOpen Loop Acceleration Control.In open loop, the controlsystem is previously con figuredto seque nee the start ingmechanism in a prescribed manner, usually based on time. In openloop control, drive-operatingparameters such as current,torque,or speed do not in flue ne

50、eseque nee operati on. This methodpresumes that the eon trol desig ner has adequately modeled drive system performa nee on the conv eyor. For larger or more complex belts, Closed Loop or Feedback con trol may he utilized. In closed loop control, during starting, the control system monitors via sen s

51、ors drive operat ing parameters such as curre nt level of the motor, speed of the belt, or force on the belt, and modifies the startingsequenee to control,limit, or optimize one or woreparameters.Closed loop eontrol systems modify the startingapplied force betwee n an empty and fully loaded eon veyo

52、r. The eonstants in the mathematical model related to the measured variable versus the system drive resp onse are termed the tuning eonstants.These eonstantsmust be properly adjusted forsuccessful applicationto each conveyor. The most commorschemesfor closed loop eontrolof conveyor starts are tachom

53、eterfeedback for speed eon trol and load cell force or drive force feedback for torque eontrol. On some complex systems, It is desirable to have the closed loop con trol system adjust itself for various eneountered conveyor eonditions.This is termedAdaptive Control. These extremes can involve vast v

54、ariations in loadings, temperature of the belting,location of the loadingon the profile, or multiple drive options on the eonveyor. There are three com mon adaptive methods. The first invo Ives decisi ons made before the start, or RestartConditioning.If theeontrol system could know that the belt is

55、empty, it would reduce initialforce and lengthen the applicationof acceleration forceto full speed. If the belt is loaded, the eon trol system would apply prete nsion forces un der stall for less time and supply sufficient torque to adequately accelerate the belt in a timelymanner. Since the belt on

56、ly becameloaded during previous running by load ing the drive, the average drive curre nt can be sampled whe n running and retai ned in a first-i n-first-out buffer memory that reflects the belt conveyanee time. Then at shutdown the FIFO average maybe use4 to preconditionsomeopen loop and closed loo

57、pset points for the next start. The second method invoIves decisions that are based on drive observations that occur during initial starting or Motion Proving. This usually invoIves a comparison In time of the drive current or force versus the belt speed. if the drive current or force required early

58、 in the sequenee is low and motion is initiated, the belt must be unioaded. If the drive current or force required is high and motion is slow in start ing, the conv eyor must be loaded. This decisi on can be divided in zones and used to modify the middle and finish of the start seque nee con trol. The third method invo Ives a comparis on of the belt speed versus time for this start against historical limits of belt accelerati on, or Accelerati on Env elope Monitoring. At start, the belt speed is measured versus time.This is compared with