煤矿业带式输送机几种软起动方式的比较外文翻译、中英文翻译、带式输送机外文文献翻译

1 外文原文： A Comparison of Soft Start Mechanisms for Mining Belt Conveyors Michael L. Nave, P.E. CONSOL Inc. 1800 Washington Road Pittsburgh, PA 15241 Belt Conveyors are an important method for transportation 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 performance, life cost, and reliability of the conveyor. This paper examines applications of each starting method within the coal mining industry. INTRODUCTION The force required to move a belt conveyor must be transmitted by the drive pulley via friction between the drive pulley and the belt fabric. In order to transmit power there must be a difference in the belt tension as it approaches and leaves the drive pulley. These conditions are true for steady state running, starting, and stopping. Traditionally, belt designs are based on static calculations of running forces. Since starting and stopping are not examined in detail, safety factors are applied to static loadings (Harrison, 1987). This paper will primarily address the starting or acceleration duty of the conveyor. The belt designer must control starting acceleration to prevent excessive tension in the belt fabric and forces in the belt drive system (Suttees, 1986). High acceleration forces can adversely affect the belt fabric, belt splices, drive pulleys, idler pulleys, shafts, bearings, speed reducers, and couplings. Uncontrolled acceleration forces can cause belt conveyor system performance problems with vertical curves, excessive belt take-up movement, loss of drive pulley friction, spillage of materials, and festooning of the belt fabric. The belt designer is confronted with two problems, The belt drive system must produce a minimum torque powerful enough to start the conveyor, and controlled such that the acceleration forces are within safe 2 limits. Smooth starting of the conveyor can be accomplished by the use of drive torque control equipment, either mechanical or electrical, or a combination of the two (CEM, 1979). SOFT START MECHANISM EVALUATION CRITERION What is the best belt conveyor drive system? The answer depends on many variables. The best system is one that provides acceptable control for starting, running, and stopping at a reasonable cost and with high reliability (Lewdly and Sugarcane, 1978). Belt Drive System For the purposes of this paper we will assume that belt conveyors are almost always driven by electrical prime movers (Goodyear Tire and Rubber, 1982). The belt drive system shall consist of multiple components including the electrical prime mover, the electrical motor starter with control system, the motor coupling, the speed reducer, the low speed coupling, the belt drive pulley, and the pulley 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 drive system components are located in the fresh air, non-permissible, areas of the mine, or in non-hazardous, National Electrical Code, Article 500 explosion-proof, areas of the surface of the mine. Belt Drive Component Attributes Size. Certain drive components are available and practical in different size ranges. For this discussion, we will assume that belt drive systems range from fractional horsepower to multiples of thousands of horsepower. Small drive systems are often below 50 horsepower. Medium systems range from 50 to 1000 horsepower. Large systems can be considered above 1000 horsepower. Division of sizes into these groups is entirely arbitrary. Care must be taken to resist the temptation to over motor or under motor a belt flight to enhance standardization. An over motored drive results in poor efficiency and the potential for high torques, while an under motored drive could result in destructive overspending on regeneration, or overheating with shortened motor life (Lords, et al., 1978). 3 Torque Control. 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 starting torque is often the limit of rating of the belt carcass, belt splice, pulley lagging, or shaft deflections. On larger belts and belts with optimized sized components, torque limits of 110% through 125% are common (Elberton, 1986). In addition to a torque limit, the belt starter may be required to limit torque increments that would stretch belting and cause traveling waves. An ideal starting control system would apply a pretension torque to the belt at rest up to the point of breakaway, or movement of the entire belt, then a torque equal to the movement requirements of the belt with load plus a constant torque to accelerate the inertia of the system components from rest to final running speed. This would minimize system transient forces and belt stretch (Shultz, 1992). Different drive systems exhibit varying ability to control the application of torques to the belt at rest and at different speeds. Also, the conveyor itself exhibits two extremes of loading. An empty belt normally presents the smallest required torque for breakaway and acceleration, while a fully loaded belt presents 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 arrangement, to a 10/1 ranges for an inclined or complex belt profile. Thermal Rating. During starting and running, each drive system may dissipate waste heat. The waste heat may be liberated in the electrical motor, the electrical controls, the couplings, the speed reducer, or the belt braking system. The thermal load of each start Is dependent on the amount of belt load and the duration of the start. The designer must fulfill the application requirements for repeated starts after running the conveyor at full load. Typical mining belt starting duties vary from 3 to 10 starts per hour equally spaced, or 2 to 4 starts in succession. Repeated starting may require the dreading or over sizing of system components. There is a direct relationship between thermal rating for repeated 4 starts and costs. Variable Speed. Some belt drive systems are suitable for controlling the starting torque and speed, but only run at constant speed. Some belt applications would require a drive system capable of running for extended periods at less than full speed. This is useful when the drive load must be shared with other drives, the belt is used as a process feeder for rate control of the conveyed material, the belt speed is optimized for the haulage rate, the belt is used at slower speeds to transport men or materials, or the belt is run a slow inspection or inching speed for maintenance purposes (Hager, 1991). The variable speed belt drive will require a control system based on some algorithm to regulate operating speed. Regeneration or Overhauling Load. Some belt profiles present the potential for overhauling loads where the belt system supplies energy to the drive system. Not all drive systems have the ability to accept regenerated energy from the load. Some drives can accept energy from the load and 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. Some belt profiles switch from motoring to regeneration during operation. Can the drive system accept regenerated energy of a certain magnitude for the application? Does the drive system have to control or modulate the amount of retarding force during overhauling? Does the overhauling occur when running and starting? Maintenance and Supporting Systems. Each drive system will require periodic preventative maintenance. Replaceable items would include motor brushes, bearings, brake pads, dissipation resistors, oils, and cooling water. If the drive system is conservatively engineered and operated, the lower stress on consumables will result in lower maintenance costs. Some drives require supporting systems such as circulating oil for lubrication, cooling air or water, environmental dust filtering, or computer instrumentation. The maintenance of the supporting 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 first capital cost to acquire the drive, the cost to install 5 and commission 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 different locations. The designer strives to meet all system performance requirements at lowest total cost. Often more than one drive system may satisfy all system performance criterions at competitive costs. Complexity. The preferred drive arrangement is the simplest, such as a single motor driving through a single head pulley. However, mechanical, economic, and functional requirements often necessitate the use of complex drives. The belt designer must balance the need for sophistication against the problems that accompany complex systems. Complex systems require additional design engineering for successful deployment. An often-overlooked cost in a complex system is the cost of training onsite personnel, or the cost of downtime as a result of insufficient training. SOFT START DRIVE CONTROL LOGIC Each drive system will require a control system to regulate the starting mechanism. The most common type of control used on smaller to medium sized drives with simple profiles is termed Open Loop Acceleration Control. In open loop, the control system is previously configured to sequence the starting mechanism in a prescribed manner, usually based on time. In open loop control, drive-operating parameters such as current, torque, or speed do not influence sequence operation. This method presumes that the control designer has adequately modeled drive system performance on the conveyor. For larger or more complex belts, Closed Loop or Feedback control may he utilized. In closed loop control, during starting, the control system monitors via sensors drive operating parameters such as current level of the motor, speed of the belt, or force on the belt, and modifies the starting sequence to control, limit, or optimize one or wore parameters. Closed loop control systems modify the starting applied force between an empty and fully loaded conveyor. The constants in the mathematical model related to the measured variable versus the system drive response are termed the tuning 6 constants. These constants must be properly adjusted for successful application to each conveyor. The most common schemes for closed loop control of conveyor starts are tachometer feedback for speed control and load cell force or drive force feedback for torque control. On some complex systems, It is desirable to have the closed loop control system adjust itself for various encountered conveyor conditions. This is termed Adaptive Control. These extremes can involve vast variations in loadings, temperature of the belting, location of the loading on the profile, or multiple drive options on the conveyor. There are three common adaptive methods. The first involves decisions made before the start, or Restart Conditioning. If the control system could know that the belt is empty, it would reduce initial force and lengthen the application of acceleration force to full speed. If the belt is loaded, the control system would apply pretension forces under stall for less time and supply sufficient torque to adequately accelerate the belt in a timely manner. Since the belt only became loaded during previous running by loading the drive, the average drive current can be sampled when running and retained in a first-in-first-out buffer memory that reflects the belt conveyance time. Then at shutdown the FIFO average may be use4 to precondition some open loop and closed loop set points for the next start. The second method involves decisions that are based on drive observations that occur during initial starting or Motion Proving. This usually involves a comparison In time of the drive current or force versus the belt speed. if the drive current or force required early in the sequence is low and motion is initiated, the belt must be unloaded. If the drive current or force required is high and motion is slow in starting, the conveyor must be loaded. This decision can be divided in zones and used to modify the middle and finish of the start sequence control. The third method involves a comparison of the belt speed versus time for this start against historical limits of belt acceleration, or Acceleration Envelope Monitoring. At start, the belt speed is measured versus time. This is compared with two limiting belt speed curves that are retained in control system memory. The first curve profiles the empty belt when accelerated, and 7 the second one the fully loaded belt. Thus, if the current speed versus time is lower than the loaded profile, it may indicate that the belt is overloaded, impeded, or drive malfunction. If the current speed versus time is higher than the empty profile, it may indicate a broken belt, coupling, or drive malfunction. In either case, the current start is aborted and an alarm issued. CONCLUSION The best belt starting system is one that provides acceptable performance under all belt load Conditions at a reasonable cost with high reliability. No one starting system meets all needs. The belt designer must define the starting system attributes that are required for each belt. In general, the AC induction motor with full voltage starting is confined to small belts with simple profiles. The AC induction motor with reduced voltage SCR starting is the base case mining starter for underground belts from small to medium sizes. With recent improvements, the AC motor with fixed fill fluid couplings is the base case for medium to large conveyors with simple profiles. The Wound Rotor Induction Motor drive is the traditional choice for medium to large belts with repeated starting duty or complex profiles that require precise torque control. The DC motor drive, Variable Fill Hydrokinetic drive, and the Variable Mechanical Transmission drive compete for application on belts with extreme profiles or variable speed at running requirements. The choice is dependent on location environment, competitive price, operating energy losses, speed response, and user familiarity. AC Variable Frequency drive and Brush less DC applications are limited to small to medium sized belts that require precise speed control due to higher present costs and complexity. However, with continuing competitive and technical improvements, the use of synthesized waveform electronic drives will expand. 8 译文： 煤矿业 带式输送机几种软起动方式的比较 Michael 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（ Harrison 1987）。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) 。 9 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 10 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、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