外文翻譯--煤礦業(yè)帶式輸送機(jī)幾種軟起動(dòng)方式的比較(已修改)
2025-06-01 06:20 本頁(yè)面
【正文】 大連交通大學(xué)信息工程學(xué)院 2020 屆本科畢業(yè)生畢業(yè)設(shè)計(jì) (論文 )外文翻譯 1 A Comparison of Soft Start Mechanisms for Mining Belt Conveyors 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 takeup 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 limits. Smooth starting of the conveyor can be acplished by the use of drive torque control equipment, either mechanical or electrical, or a bination 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 大連交通大學(xué)信息工程學(xué)院 2020 屆本科畢業(yè)生畢業(yè)設(shè)計(jì) (論文 )外文翻譯 2 electrical prime movers (Goodyear Tire and Rubber, 1982). The belt drive system shall consist of multiple ponents 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 ponent to the particular application. For the purpose of this paper, we will assume that all drive system ponents are located in the fresh air, nonpermissible, areas of the mine, or in nonhazardous, National Electrical Code, Article 500 explosionproof, areas of the surface of the mine. Belt Drive Component Attributes Size Certain drive ponents 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
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