有关带式输送机驱动装置设计的一些研究-外文翻译
带式输送机英文文献翻译
带式输送机英文文献翻译原文Transporting machine to press the operation way can is divided into:1:The leather belt type transports machine 2:Is spiral to transport machine 3:The Dou type promotes machine 4:The roller transports machine 5:Calculate to transport machine 6:The plank chain transports machine 7:The net takes to transport machine 8:The chain transports machine.1.ParameterIs general according to various condition of request, material shipping point that the material transports system, relevant of the production craft process and material of characteristic etc. to make sure each main parameter.①Transport ability:The ability oftransporting the transporting of machine means unit for time inside transport of material quantity.While transporting to spread a form material, with the quality or physical volume calculation that the per hour transports a material;At transport into a piece product, with the number of items calculation that the per hour transports.②Transport speed:The exaltation transports speed to improve the ability of transporting.When being making to lead a piece by belt conveyer and transporting length was more big, transport speed to gradually enlarge.But the take type of high-speed operation transports machine to need to notice vibration, Zao voice and start and make etc. problem.For use chain as lead a piece of transport machine,transporting the speed should not lead greatly, in order to prevent the aggrandizement power carry alotus.Carry on transporting of craft operation machine at the same time, transporting the speed should press to produce a craft to request an assurance.③Reach a size:Transport reaching of machine a size to include belt conveyer width, lath width and anticipate Dou capacity, piping diameter and container all of etc.s.These reach a sizes to all directly influence to transport machine of transport ability.④Transport length and QingCape:Transport circuit length and Qing Cape size to directly influence the total resistance of transporting the machine and need of power.2.Transport a machine the spot application wayConstitute to carry on explaining in detail from the take type machine system first:Leather belt's transporting machine is to spread a form material to transport and pack to unload an equipments most importantly, can extensively used for the mineral mountain, metallurgy, building materials, chemical engineering, electric power, industrial realms like food processing,etc, in the coal mine, metal mineral, the steel business enterprise, port, grounds like cement works,etc a great deal of application that can see skin machine, transporting the machine can not only complete to spread a transporting of form material, but also can transport into a piece material, butbasis use location, work environment, transport the dissimilarity of material category, will also have bigger difference in its design and the application;Modernization of transport the machine system has higher request to the dust palliative, is this, in each the device that transfer place and establish and sprinkle water and gather a dust, transport machine and follow line in the tape will establish and defend a breeze cover or block an aerofoil, system from list the machine constitute of, to work in the whole machine system of operate and fix to say, want and have a foothold and divide the single machine of the tube at oneself, and want to understand mutual contact between systems, list machine again is constitute to°from many partses,only work well the daily maintenance of each parts maintains and makes it is placed in good work status so as to ensure the safe movement of equipments;We generally will transport the use place, work environment of machine according to the take type, technique function and transport material category to wait various dissimilarity with satisfy various forms of homework work condition, in addition to in addition to transporting machine, the in general use leather belt of more adoption also various special kind tapes of new structure transport machine and have a mainly having of the representative among them:Big Qing Cape take type machine, deep slot take type machine and press take type machine, take care of the formtake type, the air cushion take type, the flat surface turn take type, the line friction type, wave-like in shape the belt conveyer type blocking a side transport machine etc. and carry on a thin method for turning and canning exist various classifications and make following introduction now:Press the use classification, there is in general use ambulation type, under the well choice type, the strip mine is used a fixed type, special kind structure type, can move a place type and transport machine, load machine appropriation redistribution function type, the big Qing Cape type transports machine etc., generally speaking transport machine inside the short distance factory can complete level, up the luck or bottomcarries, canning go against the wood grain type leather belt machine can be used for double to transport a material, hang arm machine usually install anticipate on board in the heap, and can turn round, line up the function of soil or cloth by realization, but Gao Jia Ji propped up by in the door usually match with other spread and anticipate and handle an equipments common use, for example give or get an electric shock and constuct a medium application in water, can install standard in the center frame, the machine's mounting places on the track Zhen, easy to move and place;Press the category of transporting the material to categorize, have the generally lax material is used of, the strong and tough material is used of and list piece theleather belt used in material transport machine etc. and press the rubber conveyance takes a loading segment of position to categorize, include a leather belt loading segment at top of and loading segment at underneath of and at the same time loading segment at up underneath of double to transport machine three, the use double can distinguish to transporting machine at up branch and bottom branch transport a material, but for keeping material contact noodles don't produce a change and need to bring in to go to the rubber to be periodically inside out.3.CategorizeTransporting machine generally and pressing already didn't lead piece to carry on a classification and had to lead a transporting of piece machine to generallyinclude to lead a piece, loading to reach a piece, drive device, bring to the stretch device and change to accept an etc. to the device and.Lead a piece to in order to deliver to lead dint, can adopt belt conveyer and lead chain or steel wire rope;The loading reaches a piece to in order to accept to put a material and has already anticipated Dou and bracket or mourns to have...etc.;Drive device to transport machine with the power, generally from electric motor, decelerate a machine and make machine(stop a machine) etc. to constitute;Bring to the stretch to equip to generally have the Luo pole the type and heavy hammer type 2 kind, can make to lead a piece to keep certain tension and hang a degree, transport machine by assurance normaloperation;Pay to accept a piece to in order to accept to give to lead piece or loading to reach a piece, can adopt to give Gun and roll an etc..Having the structure characteristics that lead the transporting of piece machine is:Be delivered a material and pack reaching with the loading leading a link together inside the piece, or directly pack in leading a piece(is like belt conveyer), led a piece to once round each roller or the chain round beginning and end and connect with each other, formation include and deliver a having of material carry branch and don't deliver a material of have never carried shutting of branch and match wreath road, make use of lead continuous sport of piece and transport a material.This type ofly transporting model is numerous,there is mainly a take type transporting a machine, plank type and transporting a machine, small car type and transporting machine, escalator, automatic sidewalk, paring off plank and transporting machine, covering up and paring off plank and transporting a machine, Dou type and transporting a machine, Dou type and promoting machine and hanging and transporting machine and build on stilts a cableway...etc..The structure that didn't lead transporting of piece machine constitutes each not same, use to the work of transporting the material to reach a piece as well not same.Their structure characteristicses are:Make use of a work to reach a revolving of piece to exercise or the back and forth exercise, or make useof lie quality to make the material transport forward in the fluxion in the piping.For example, the Gun son transports the work of machine to reach the piece as a series of Gun son, the Gun son makes to revolve sport to transport a material;Is spiral to transport the work of machine to reach a piece for spiral, helix at anticipate and make to revolve sport in the slot with follow anticipate slot to push to send a material;The vibration transports the work of machine to reach piece in order to anticipate slot, anticipate slot to make back and forth sport with transport Be placed to among them of material etc..Install(1)The fixed type transports machine should by rule gearing method gearing atfix of foundation up.The ambulation type transports machine formally before circulating and should live wheel with the wedge Xie or uses to make a machine to stop.So as not to take place to take a stroll in the work, there is the passage that many sets , between machine and machine, there shoulded be one meter between wall and machine while transporting a parallel homework of machine.(2)The beard checks an each operation part, tape to take to button up to equip with loading before using whether normal, whether protection equipments iswell-found.The tape rises a tight degree beard before starting the adjustment is to suitable extent.(3)Leather belt's transporting machine should get empty to carry a start.Waitingto revolve normal rear can go into to anticipate.Drive after forbiding to go into first to anticipate.(4)There are few set that when transport machine to establish to circulate should from unload to anticipate to carry a beginning, the sequence starts.After revolving as usual all, the square can go into to anticipate.(5)Appear in the movement when the tape runs to be partial to a phenomenon should park the car adjustment, can not force an use, so as not to wear away edge and increment burden.(6)Work environment and be sent material temperature not to must be higher than 50 ℃ and be lowerthan-10 ℃ .Can not transport the material of having sour alkaline oil andorganic melting agent composition.(7)Forbid pedestrian or multiply by a person on the belt conveyer.(8)Have to stop going into first to anticipate before parking the car, wait leather belt up save to anticipate to unload to the utmost a square can park the car.(9)Transporting the machine electric motor has to insulate good.The ambulation type transports machine electric cable to pull and drag along indiscriminately.The dynamoelectric confidential credibility connects ground.(10)The leather belt beats slippery strictly forbid to by hand pull leather belt, so as not to take place trouble.5.Adjust to try(1) Each equipments with meticulouscare adjusts to try to transport machine after installing and satisfies a drawing request.(2) Each deceleration machine exercises parts to add to note to correspond lubricant.(3) The gearing after transporting machine to attain to request each single set equipments carries on beginning to work to make run-in, and knot to put together to adjust to try to transport machine to satisfy an operative request. (4) Adjust to try the electricity part of transporting the machine.Include to connect adjusting of line and action to try to the normal regulations electricity, make the equipments have good function, attain the function and status of design.6.Transport machine to block knothole 2kinds of boring crafts(1)Blow up boring:The material after the irradiation of continuous laser and centrally forms one cave pit, then from and laser beam the coaxial oxygen flow to clean meltdown material and form one bore very quickly.The size of general bore is as thick relevant as plank, blow up to bore hole the average diameter as thick plank half, therefore blow up to bore hole bore path bigger to thicker plank, and not circle, should not in requesting higher spare parts use(if the petroleum Shai sews a tube), can be used for a waste up.In addition because of bore hole use of oxygen pressure with incise homology, splash a little bit greatly.(2)Pulse boring:The pulse laser that adopts high peak value power makes alittle amount material melt or vaporizes, in common use air or nitrogen spirit are to lend support to air and oxidize to make bore expand because of putting heat by decrease, the air pressure more incises of the oxygen pressure is small.The particle jet with small creation of each pulse laser gradually goes deep into, therefore slab boring time takes several seconds.Once bore hole completion, immediately change assistance air into oxygen to carry on incising.Boring hole diameter like this is smaller, its boring quality is better than to blow up boring.Not only should have higher exportation power for the laser machine used by this;The time and space characteristic that more important time ties, therefore the general crosscurrent carbon dioxide laser machine can notadapt to the request that the laser incises.In addition the pulse bores hole to also have the more dependable spirit road the control system to carry out cutting over of air category, air pressure and bore hole a horary control.译文：输送机按运作方式可以分为：1：皮带式输送机2：螺旋输送机3：斗式提升机4：滚筒输送机5：计量输送机6：板链输送机7：网带输送机8：链条输送机。
高速带式输送机的设计——外文翻译、中英文翻译
附件A高速带式输送机的设计G. Lodewijks，荷兰摘要本文主要探讨高速带式输送机设计方面的问题。
带式输送机的输送量取决于输送带的速度、传送带宽度和托辊槽形角。
然而输送带速度的选择又受到各种实际条件的限制，在本文有这方面的讨论。
输送带速度也影响传送带的性能，例如它的能源消耗和它连续运行的稳定性。
一种计算输送带的能源消耗的方法就是通过考虑运输过程中的各种能量损耗来进行估算的。
输送带速度的不同使得安全系数的要求也各不相同，这也影响输送带所要求的强度。
一种新的计算输送带速度对安全系数的影响的方法在本文中被介绍。
最后，输送带速度的冲击对各组成部分的选择和对中转站设计的影响也在本文中被讨论。
1 概述过去的研究已经证实使用窄带输送机的经济可行性，输送带的速度变快要求输送带的宽度随之变宽，低速输送机适于长距离输送。
例如图[1] - [5]。
现在，传送带以8 m/s 的速度运行是没有问题的。
无论怎样，输送带速度在10m/s到20 m/s在技术上是(动态地)可行的，并且也许在经济上也是可行的。
本文将输送带速度在10和20 m/s之间的定义为高速。
输送带速度在10m/s之下的定义为低速。
使用高速输送带的目的并不在于它本身。
如果使用高速输送带不是经济上有利，或则，如果安全和可靠的操作没有保证的，那么就应该选择低速输送带。
输送带速度的选择是总的设计过程的一部分。
静态或稳定的设计方法决定了带式输送机的优化设计。
在这些设计方法中输送带被认为是刚性的，静止的。
这增加了输送机稳定运行的质量和也决定了带式输送机各零部件的尺寸。
稳定操作包括传送带稳定运行时的张力、相对各种物料载荷的能量消耗和相关的工作环境情况。
应该体会到找到最优的设计不是一次性的努力，而是一个反复的过程[6]。
优化设计，开始于优化的决心，终于符合要求的确定的控制算法和组成输送机的各零部件确定的位置和尺寸的大小，例如驱动，闸和飞轮，可由动态设计方法确定。
在这些设计方法中，也涉及动态分析，输送带可看作是一个三维的弹性体。
机械毕业设计英文外文翻译95带式输送机及其牵引系统
翻译部分英文原文Belt Conveying Systems Development of driving system Among the methods of material conveying employed，belt conveyors play a very important part in the reliable carrying of material over long distances at competitive cost．Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to doso．Nowadays，bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine)．The ability to control driveacceleration torque is critical to belt conveyors’ performance．An efficient drive system should be able to provide smooth，soft starts while maintaining belt tensions within the specified safe limits．For load sharing on multiple drives．torque and speed control are also important considerations in the drive system’s design. Due to the advances in conveyor drive control technology，at present many more reliable．Cost-effective and performance-driven conveyor drivesystems covering a wide range of power are available for customers’choices[1].1 Analysis on conveyor drive technologies1．1 Direct drivesFull-voltage starters．With a full-voltage starter design，the conveyor head shaft is direct-coupled to the motor through the gear drive．Direct full-voltage starters are adequate for relatively low-power,simple-profile conveyors．With direct fu11-voltage starters．no control is provided for various conveyor loads and．depending on the ratio between fu11-and no-1oad power requirements，empty starting times can be threeor four times faster than full load．The maintenance-free starting system is simple，low-cost and very reliable．However, they cannot control starting torque and maximum stall torque；therefore．they are limited to the low-power, simple-profile conveyor belt drives．Reduced-voltage starters．As conveyor power requirements increase，controlling the applied motor torque during the acceleration period becomes increasingly important．Because motor torque 1s a function of voltage，motor voltage must be controlled．This can be achieved through reduced-voltage starters by employing a silicon controlledrectifier(SCR)．A common starting method with SCR reduced-voltage starters is to apply low voltage initially to take up conveyor belt slack．and then to apply a timed linear ramp up to full voltage and belt speed．However, this starting method will not produce constant conveyor belt acceleration．When acceleration is complete．the SCRs,which control the applied voltage to the electric motor． are locked in full conduction, providing fu11-line voltage to the motor．Motors with higher torque and pull—up torque，can provide better starting torque when combined with the SCR starters, which are available in sizes up to 750 KW．Wound rotor induction motors．Wound rotor induction motors are connected directly to the drive system reducer and are a modified configuration of a standard AC induction motor．By inserting resistance in series with the motor’s rotor windings．the modified motor control system controls motor torque．For conveyor starting，resistance is placed in series with the rotor for low initial torque．As the conveyor accelerates，the resistance is reduced slowly to maintain a constant acceleration torque．On multiple-drive systems．an external slip resistor may be left in series with the rotor windings to aid in load sharing．The motor systems have a relatively simple design．However, the control systems for these can be highly complex，because they are based on computercontrol of the resistance switching．Today，the majority of control systems are custom designed to meet a conveyor system’s particular specifications．Wound rotor motors are appropriate for systems requiring more than 400 kW ．DC motor．DC motors．available from a fraction of thousands of kW ，are designed to deliver constant torque below base speed and constant kW above base speed to the maximum allowable revolutions perminute(r/min)．with the majority of conveyor drives, a DC shunt wound motor is used．Wherein the motor’s rotating armature is connected externally．The most common technology for controlling DC drives is a SCR device． which allows for continual variable-speed operation．The DC drive system is mechanically simple, but can include complex custom-designed electronics to monitor and control the complete system．This system option is expensive in comparison to other soft-start systems．but it is a reliable,cost-effective drive in applications in which torque,1oad sharing and variable speed are primary considerations．DC motors generally are used with higher-power conveyors，including complex profile conveyors with multiple-drive systems，booster tripper systems needing belt tension control and conveyors requiring a wide variable-speed range．1．2 Hydrokinetic couplingHydrokinetic couplings，commonly referred to as fluid couplings．are composed of three basic elements; the driven impeller, which acts as a centrifugal pump；the driving hydraulic turbine known as the runner and a casing that encloses the two power components．Hydraulic fluid is pumped from the driven impeller to the driving runner, producing torque at the driven shaft．Because circulating hydraulic fluid produces the torque and speed，no mechanical connection is required between the driving and driven shafts．The power produced by this coupling is based on the circulated fluid’s amount and density and the torque in proportion to inputspeed．Because the pumping action within the fluid coupling depends on centrifugal forces．the output speed is less than the input speed．Referred to as slip．this normally is between l% and 3%．Basic hydrokinetic couplings are available in configurations from fractional to several thousand kW ．Fixed-fill fluid couplings．Fixed-fill fluid couplings are the most commonly used soft-start devices for conveyors with simpler belt profiles and limited convex/concave sections．They are relativelysimple,1ow-cost,reliable,maintenance free devices that provide excellent soft starting results to the majority of belt conveyors in use today．Variable-fill drain couplings．Drainable-fluid couplings work on the same principle as fixed-fill couplings．The coupling’s impellers are mounted on the AC motor and the runners on the driven reducer high-speed shaft．Housing mounted to the drive base encloses the working circuit．The coupling’s rotating casing contains bleed-off orifices that continually allow fluid to exit the working circuit into a separate hydraulic reservoir．Oil from the reservoir is pumped through a heat exchanger to a solenoid-operated hydraulic valve that controls the filling of the fluid coupling．To control the starting torque of a single-drive conveyor system，the AC motor current must be monitored to provide feedback to the solenoid control valve．Variable fill drain couplings are used in medium to high-kW conveyor systems and are available in sizes up to thousands of kW ．The drives can be mechanically complex and depending on the control parameters．the system can be electronically intricate．The drive system cost is medium to high, depending upon size specified．Hydrokinetic scoop control drive．The scoop control fluid coupling consists of the three standard fluid coupling components：a driven impeller, a driving runner and a casing that encloses the working circuit．The casing is fitted with fixed orifices that bleed apredetermined amount of fluid into a reservoir．When the scoop tube is fully extended into the reservoir, the coupling is l00 percent filled．The scoop tube, extending outside the fluid coupling，is positioned using an electric actuator to engage the tube from the fully retracted to the fully engaged position．This control provides reasonably smooth acceleration rates．to but the computer-based control system is very complex．Scoop control couplings are applied on conveyors requiring single or multiple drives from l50 kW to 750 kW.1．3 Variable-frequency control(VFC)Variable frequency control is also one of the direct drive methods．The emphasizing discussion about it here is because that it has so unique characteristic and so good performance compared with other driving methods for belt conveyor． VFC devices Provide variable frequency and voltage to the induction motor, resulting in an excellent starting torque and acceleration rate for belt conveyor drives．VFC drives．available from fractional to several thousand(kW ), are electronic controllers that rectify AC line power to DC and，through an inverter, convert DC back to AC with frequency and voltage contro1．VFC drives adopt vector control or direct torque control(DTC)technology，and can adopt different operating speeds according to different loads．VFC drives can make starting or stalling according to any given S-curves．realizing the automatic track for starting or stalling curves．VFC drives provide excellent speed and torque control for starting conveyor belts．and can also be designed to provide load sharing for multiple drives．easily VFC controllers are frequently installed on lower-powered conveyor drives，but when used at the range of medium-high voltage in the past．the structure of VFC controllers becomes very complicated due to the limitation of voltage rating of power semiconductor devices，the combination of medium-high voltage drives and variable speed is often solved withlow-voltage inverters using step-up transformer at the output，or with multiple low-voltage inverters connected in series．Three-level voltage-fed PWM converter systems are recently showing increasing popularity for multi-megawatt industrial drive applications because of easy voltage sharing between the series devices and improved harmonic quality at the output compared to two-level converter systems With simple series connection of devices．This kind of VFC system with three 750 kW /2．3kV inverters has been successfully installed in ChengZhuang Mine for one 2．7-km long belt conveyor driving system in following the principle of three-level inverter will be discussed in detail．2 Neutral point clamped(NPC)three-level inverter using IGBTsThree-level voltage-fed inverters have recently become more and more popular for higher power drive applications because of their easy voltage sharing features．1ower dv/dt per switching for each of the devices，and superior harmonic quality at the output．The availability of HV-IGBTs has led to the design of a new range of medium-high voltage inverter using three-level NPC topology．This kind of inverter can realize a whole range with a voltage rating from 2．3 kV to 4．1 6 kV Series connection of HV-IGBT modules is used in the 3．3 kV and 4．1 6 kV devices．The 2．3 kV inverters need only one HV-IGBT per switch[2,3].2．1 Power sectionTo meet the demands for medium voltage applications．a three-level neutral point clamped inverter realizes the power section．In comparison to a two-level inverter．the NPC inverter offers the benefit that three voltage levels can be supplied to the output terminals，so for the same output current quality，only 1/4 of the switching frequency is necessary．Moreover the voltage ratings of the switches in NPC inverter topology will be reduced to 1/2．and the additional transient voltage stress on the motor can also be reduced to 1/2 compared to that of atwo-level inverter．The switching states of a three-level inverter are summarized in Table 1．U．V and W denote each of the three phases respectively；P N and O are the dc bus points．The phase U，for example，is in state P(positive busvoltage)when the switches S1u and S2uare closed，whereas it is in stateN (negative bus voltage) when the switches S3u and S4uare closed．Atneutral point clamping，the phase is in O state when either S2u or S3uconducts depending on positive or negative phase current polarity，respectively．For neutral point voltage balancing，the average current injected at O should be zero．2．2 Line side converterFor standard applications．a l2-pulse diode rectifier feeds the divided DC-link capacitor．This topology introduces low harmonics on the line side．For even higher requirements a 24-pulse diode rectifier can be used as an input converter．For more advanced applications where regeneration capability is necessary, an active front．end converter can replace the diode rectifier, using the same structure as the inverter．2．3 Inverter controlMotor Contro1．Motor control of induction machines is realized by using a rotor flux．oriented vector controller．Fig．2 shows the block diagram of indirect vector controlled drive that incorporates both constant torque and high speed field-weakening regions where the PW M modulator was used．In this figure，the commandflux is generated as function of speed．The feedback speed is addedwith the feed forward slip command signal . the resulting frequencysignal is integrated and then the unit vector signals(cos and sin )aregenerated．The vector rotator generates the voltage and anglecommands for the PW M as shown．PWM Modulator．The demanded voltage vector is generated using anelaborate PWM modulator．The modulator extends the concepts ofspace-vector modulation to the three-level inverter．The operation can be explained by starting from a regularly sampled sine-triangle comparison from two-level inverter．Instead of using one set of reference waveforms and one triangle defining the switching frequency， thethree-level modulator uses two sets of reference waveforms Ur1and Ur2andjust one triangle．Thus, each switching transition is used in an optimal way so that several objectives are reached at the same time．Very low harmonics are generated．The switching frequency is low and thus switching losses are minimized．As in a two-level inverter, a zero-sequence component can be added to each set of reference waveform s in order to maximize the fundamental voltage component．As an additional degree of freedom，the position of the reference waveform s within the triangle can be changed．This can be used for current balance in the two halves of the DC-1ink．3 Testing resultsAfter Successful installation of three 750 kW /2．3 kV three-level inverters for one 2．7 km long belt conveyor driving system in Chengzhuang Mine．The performance of the whole VFC system was tested．Fig．3 is taken from the test，which shows the excellent characteristic of the belt conveyor driving system with VFC controller．Fig．3 includes four curves．The curve 1 shows the belt tension．From the curve it can be find that the fluctuation range of the belt tension is very smal1．Curve 2 and curve 3 indicate current and torque separately．Curve 4 shows the velocity of the controlled belt．The belt velocity have the“s”shape characteristic．A1l the results of the test show a very satisfied characteristic for belt driving system．4 ConclusionsAdvances in conveyor drive control technology in recent years haveresulted in many more reliable．Cost-effective and performance-driven conveyor drive system choices for users．Among these choices，the Variable frequency control (VFC) method shows promising use in the future for long distance belt conveyor drives due to its excellent performances．The NPC three-level inverter using high voltage IGBTs make the Variable frequency control in medium voltage applications become much more simple because the inverter itself can provide the medium voltage needed at the motor terminals，thus eliminating the step-up transformer in most applications in the past．The testing results taken from the VFC control system with NPC three．1evel inverters used in a 2．7 km long belt conveyor drives in Chengzhuang Mine indicates that the performance of NPC three-level inverter using HV-IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive is excellent for belt conveyor driving system．中文译文：带式输送机及其牵引系统在运送大量的物料时，带式输送机在长距离的运输中起到了非常重要的竞争作用。
带式输送机技术的最新发展——外文文献翻译、中英文翻译
附录A带式输送机技术的最新发展M. A. AlspaughOverland Conveyor Co., Inc.MINExpo 2004拉斯维加斯, 内华达州，美国，9，27, 2004摘要粒状材料运输要求带式输送机具有更远的输送距离、更复杂的输送路线和更大的输送量。
为了适应社会的发展，输送机需要在系统设计、系统分析、数值仿真领域向更高层次发展。
传统水平曲线和现代中间驱动的应用改变和扩大了带式输送机发展的可能性。
本文回顾了为保证输送机的可靠性和可用性而运用数字工具的一些复杂带式输送机。
前言虽然这篇文章的标题表明在皮带输送机技术中将提出“新”发展，但是提到的大多思想和方法都已存在很长时间了。
我们不怀疑被提出一些部件或想法将是“新”的对你们大部分人来说。
所谓的“新”就是利用成熟的技术和部件组成特别的、复杂的系统；“新”就是利用系统设计工具和方法，汇集一些部件组成独特的输送机系统，并解决大量粒状原料的装卸问题；“新”就是在第一次系统试验(委任)之前利用日益成熟的计算机技术进行准确节能计算机模拟。
同样，本文的重点是特定复杂系统设计及满足长距离输送的要求。
这四个具体课题将覆盖：●托辊阻力●节能●动力分散●分析与仿真节能减小设备整体电力消费是所有项目的一个重要方面，皮带输送机是也不例外。
虽然与其他运输方法比较皮带输送机总是运输大吨位高效率的手段，但是减少带式输送机的功率消耗的方法还是很多的。
皮带输送机的主要阻力组成部分有：●托辊阻力●托辊与皮带的摩擦力●材料或输送带弯曲下垂引起的阻力●重力这些阻力加上一些混杂阻力组成输送材料所需的力。
1在一台输送长度400米的典型短距离输送机中,力可以分为如图1所示的几个部分，图中可以看出提升力所占比例最大，而阻力还是占绝大部分。
图1在高倾斜输送带中如矿用露天倾斜输送带，所受力可分解为图2所示的几个部分，其中提升力仍占巨大比例。
由于重力是无法避免的，因此没有好的方法减少倾斜式输送机所受力。
带式输送机中英文对照外文翻译文献
中英文翻译Development of belt conveyor driving systemAbstract A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the variable-frequency-control(VFC} method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three一Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.Key words belt conveyor driving system, variable-frequency-control, three-level inverter Among the methods of material conveying employed，belt conveyors play a very important part in the reliable carrying of material over long distances at competitive cost．Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to do so．Nowadays，bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine)．The ability to control drive acceleration torque is critical to belt conveyors’ performance．An efficient drive system should be able to provide smooth，soft starts while maintaining belt tensions within the specified safe limits．For load sharing on multiple drives．torque and speed control are also important considerations in the drive system’s design. Due to the advances in conveyor drive control technology，at present many more reliable．Cost-effective and performance-driven conveyor driv e systems covering a wide range of power are available for customers’choices[1].1 Analysis on conveyor drive technologies1．1 Direct drivesFull-voltage starters．With a full-voltage starter design，the conveyor head shaft is direct-coupled to the motor through the gear drive．Direct full-voltage starters are adequate for relativelylow-power, simple-profile conveyors．With direct fu11-voltage starters．no control is provided for various conveyor loads and．depending on the ratio between fu11- and no-1oad power requirements，empty starting times can be three or four times faster than full load．The maintenance-free starting system is simple，low-cost and very reliable．However, they cannot control starting torque and maximum stall torque；therefore．they are limited to the low-power,simple-profile conveyor belt drives．Reduced-voltage starters．As conveyor power requirements increase，controlling the applied motor torque during the acceleration period becomes increasingly important．Because motor torque 1s a function of voltage，motor voltage must be controlled．This can be achieved through reduced-voltage starters by employing a silicon controlled rectifier(SCR)．A common starting method with SCR reduced-voltage starters is to apply low voltage initially to take up conveyor belt slack．and then to apply a timed linear ramp up to full voltage and belt speed．However, this starting method will not produce constant conveyor belt acceleration．When acceleration is complete．the SCRs, which control the applied voltage to the electric motor．are locked in full conduction, providing fu11-line voltage to the motor．Motors with higher torque and pull—up torque，can provide better starting torque when combined with the SCR starters, which are available in sizes up to 750 KW．Wound rotor induction motors．Wound rotor induction motors are connected directly to the drive system reducer and are a modified configuration of a standard AC induction motor．By inserting resistance in series with the motor’s rotor windings．the modified motor control system controls motor torque．For conveyor starting，resistance is placed in series with the rotor for low initial torque．As the conveyor accelerates，the resistance is reduced slowly to maintain a constant acceleration torque．On multiple-drive systems．an external slip resistor may be left in series with the rotor windings to aid in load sharing．The motor systems have a relatively simple design．However, the control systems for these can be highly complex，because they are based on computer control of the resistance switching．Today，the majority of control systems are custom designed to meet a conveyor system’s particular specifications．Wound rotor motors are appropriate for systems requiring more than 400 kW ．DC motor．DC motors．available from a fraction of thousands of kW ，are designed to deliver constant torque below base speed and constant kW above base speed to the maximum allowable revolutions per minute(r/min)．with the majority of conveyor drives, a DC shunt wound motor is used．Wherein the motor’s rotating arma ture is connected externally．The most common technology for controlling DC drives is a SCR device．which allows for continual variable-speed operation．The DC drive system is mechanically simple, but can include complex custom-designed electronics to monitor and control the complete system．This system option is expensive in comparison to other soft-start systems．but it is a reliable, cost-effective drive inapplications in which torque,1oad sharing and variable speed are primary considerations．DC motors generally are used with higher-power conveyors，including complex profile conveyors with multiple-drive systems，booster tripper systems needing belt tension control and conveyors requiring a wide variable-speed range．1．2 Hydrokinetic couplingHydrokinetic couplings，commonly referred to as fluid couplings．are composed of three basic elements; the driven impeller, which acts as a centrifugal pump；the driving hydraulic turbine known as the runner and a casing that encloses the two power components．Hydraulic fluid is pumped from the driven impeller to the driving runner, producing torque at the driven shaft．Because circulating hydraulic fluid produces the torque and speed，no mechanical connection is required between the driving and driven shafts．The power produced by this coupling is based on the circulated fluid’s amount and density and the torque in proportion to input speed．Because the pumping action within the fluid coupling depends on centrifugal forces．the output speed is less than the input speed．Referred to as slip．this normally is between l% and 3%．Basic hydrokinetic couplings are available in configurations from fractional to several thousand kW ．Fixed-fill fluid couplings．Fixed-fill fluid couplings are the most commonly used soft-start devices for conveyors with simpler belt profiles and limited convex/concave sections．They are relatively simple,1ow-cost,reliable,maintenance free devices that provide excellent soft starting results to the majority of belt conveyors in use today．Variable-fill drain couplings．Drainable-fluid couplings work on the same principle as fixed-fill couplings．The coupling’s impellers are mounted on the AC motor and the runners on the driven reducer high-speed shaft．Housing mounted to the drive base encloses the working circuit．The c oupling’s rotating casing contains bleed-off orifices that continually allow fluid to exit the working circuit into a separate hydraulic reservoir．Oil from the reservoir is pumped through a heat exchanger to a solenoid-operated hydraulic valve that controls the filling of the fluid coupling．To control the starting torque of a single-drive conveyor system，the AC motor current must be monitored to provide feedback to the solenoid control valve．Variable fill drain couplings are used in medium to high-kW conveyor systems and are available in sizes up to thousands of kW ．The drives can be mechanically complex and depending on the control parameters．the system can be electronically intricate．The drive system cost is medium to high,depending upon size specified．Hydrokinetic scoop control drive．The scoop control fluid coupling consists of the three standard fluid coupling components：a driven impeller, a driving runner and a casing that encloses the working circuit．The casing is fitted with fixed orifices that bleed a predetermined amount of fluid into a reservoir．When the scoop tube is fully extended into the reservoir, the coupling is l00 percent filled．The scoop tube, extending outside the fluid coupling，is positioned using an electric actuator to engage the tube from the fully retracted to the fully engaged position．This control provides reasonably smooth acceleration rates．to but the computer-based control system is very complex．Scoop control couplings are applied on conveyors requiring single or multiple drives from l50 kW to 750 kW.1．3 Variable-frequency control(VFC)Variable frequency control is also one of the direct drive methods．The emphasizing discussion about it here is because that it has so unique characteristic and so good performance compared with other driving methods for belt conveyor．VFC devices Provide variable frequency and voltage to the induction motor, resulting in an excellent starting torque and acceleration rate for belt conveyor drives．VFC drives．available from fractional to several thousand(kW ), are electronic controllers that rectify AC line power to DC and，through an inverter, convert DC back to AC with frequency and voltage contro1．VFC drives adopt vector control or direct torque control(DTC)technology，and can adopt different operating speeds according to different loads．VFC drives can make starting or stalling according to any givenS-curves．realizing the automatic track for starting or stalling curves．VFC drives provide excellent speed and torque control for starting conveyor belts．and can also be designed to provide load sharing for multiple drives．easily VFC controllers are frequently installed on lower-powered conveyor drives，but when used at the range of medium-high voltage in the past．the structure of VFC controllers becomes very complicated due to the limitation of voltage rating of power semiconductor devices，the combination of medium-high voltage drives and variable speed is often solved with low-voltage inverters using step-up transformer at the output，or with multiple low-voltage inverters connected in series．Three-level voltage-fed PWM converter systems are recently showing increasing popularity for multi-megawatt industrial drive applications because of easy voltage sharing between the series devices and improved harmonic quality at the output compared to two-level converter systems With simple series connection ofdevices．This kind of VFC system with three 750 kW /2．3kV inverters has been successfully installed in ChengZhuang Mine for one 2．7-km long belt conveyor driving system in following the principle of three-level inverter will be discussed in detail．2 Neutral point clamped(NPC)three-level inverter using IGBTsThree-level voltage-fed inverters have recently become more and more popular for higher power drive applications because of their easy voltage sharing features．1ower dv/dt per switching for each of the devices，and superior harmonic quality at the output．The availability of HV-IGBTs has led to the design of a new range of medium-high voltage inverter usingthree-level NPC topology．This kind of inverter can realize a whole range with a voltage rating from 2．3 kV to 4．1 6 kV Series connection of HV-IGBT modules is used in the 3．3 kV and 4．1 6 kV devices．The 2．3 kV inverters need only one HV-IGBT per switch[2,3].2．1 Power sectionTo meet the demands for medium voltage applications．a three-level neutral point clamped inverter realizes the power section．In comparison to a two-level inverter．the NPC inverter offers the benefit that three voltage levels can be supplied to the output terminals，so for the same output current quality，only 1/4 of the switching frequency is necessary．Moreover the voltage ratings of the switches in NPC inverter topology will be reduced to 1/2．and the additional transient voltage stress on the motor can also be reduced to 1/2 compared to that of a two-level inverter．The switching states of a three-level inverter are summarized in Table 1．U．V and W denote each of the three phases respectively；P N and O are the dc bus points．The phase U，for example，is in state P(positive bus voltage)when the switches S1u and S2u are closed，whereas it is in state N (negative bus voltage) when the switches S3u and S4u are closed．At neutral point clamping，the phase is in O state when either S2u or S3u conducts depending on positive or negative phase current polarity，respectively．For neutral point voltage balancing，the average current injected at O should be zero．2．2 Line side converterFor standard applications．a l2-pulse diode rectifier feeds the divided DC-link capacitor．This topology introduces low harmonics on the line side．For even higher requirements a 24-pulse diode rectifier can be used as an input converter．For more advanced applications where regeneration capability is necessary, an active front．end converter can replace the dioderectifier, using the same structure as the inverter．2．3 Inverter controlMotor Contro1．Motor control of induction machines is realized by using a rotor flux．oriented vector controller．Fig．2 shows the block diagram of indirect vector controlled drive that incorporates both constant torque and high speed field-weakening regions where the PW M modulator was used．Inthis figure，the command flux is generated as function of speed．The feedback speed isadded with the feed forward slip command signal . the resulting frequency signal isintegrated and then the unit vector signals(cos and sin)are generated．The vector rotatorgenerates the voltage and angle commands for the PW M as shown．PWM Modulator．The demanded voltage vector is generated using an elaborate PWM modulator．The modulator extends the concepts of space-vector modulation to the three-level inverter．The operation can be explained by starting from a regularly sampled sine-triangle comparison from two-level inverter．Instead of using one set of reference waveforms and one triangle defining the switching frequency，the three-level modulator uses two sets of reference waveforms U r1 and U r2 and just one triangle．Thus, each switching transition is used in an optimal way so that several objectives are reached at the same time．Very low harmonics are generated．The switching frequency is low and thus switching losses are minimized．As in a two-level inverter, a zero-sequence component can be added to each set of reference waveform s in order to maximize the fundamental voltage component．As an additional degree of freedom，the position of the reference waveform s within the triangle can be changed．This can be used for current balance in the two halves of the DC-1ink．3 Testing resultsAfter Successful installation of three 750 kW /2．3 kV three-level inverters for one 2．7 km long belt conveyor driving system in Chengzhuang Mine．The performance of the whole VFC system was tested．Fig．3 is taken from the test，which shows the excellent characteristic of the belt conveyor driving system with VFC controller．Fig．3 includes four curves．The curve 1 shows the belt tension．From the curve it can be find that the fluctuation range of the belt tension is very smal1．Curve 2 and curve 3 indicate current and torque separately．Curve 4 shows the velocity of the controlled belt．The belt velocityhave the“s”shape characteristic．A1l the results of the test show a very satisfied characteristic for belt driving system．4 ConclusionsAdvances in conveyor drive control technology in recent years have resulted in many more reliable．Cost-effective and performance-driven conveyor drive system choices for users．Among these choices，the Variable frequency control (VFC) method shows promising use in the future for long distance belt conveyor drives due to its excellent performances．The NPC three-level inverter using high voltage IGBTs make the Variable frequency control in medium voltage applications become much more simple because the inverter itself can provide the medium voltage needed at the motor terminals，thus eliminating the step-up transformer in most applications in the past．The testing results taken from the VFC control system with NPC three．1evel inverters used in a 2．7 km long belt conveyor drives in Chengzhuang Mine indicates that the performance of NPC three-level inverter using HV-IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive is excellent for belt conveyor driving system．References[l] Jim Ehler. Conveyor drive technologies offer smooth, soft starts[J]. Motors& Drives, 2001(4): 28-35.[2] Sommer R, Mertens A. Medium voltage drive system with three-level NPC inverter using IGBTs[A]. IEE Colloquium on PWM Medium V oltage Drives[C]. Birmingham,2000[3] Mertens A, Sommer R, Brunotte C. Applications of medium voltage drives with IGBT three-level inverter[A]. IEE colloquium on PWM medium voltage drives[C]. Birmingham,2000中文译文：带式输送机及其牵引系统在运送大量的物料时，带式输送机在长距离的运输中起到了非常重要的竞争作用。
带式输送机外文翻译---煤矿输送带软启动机制的比较
附录英文文献A Comparison of Soft Start Mechanisms for Mining Belt ConveyorsMichael L. Nave, P.E.CONSOL Inc.1800 Washington Road Pittsburgh, PA 15241Belt 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.INTRODUCTIONThe drive pulley via friction between the drive pulley and the belt fabric must transmit the force required to move a belt conveyor. 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 (Surtees, 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 limits. Smooth starting of the conveyor can be accomplished by the use of drive torque control equipment, eithermechanical or electrical, or a combination of the two (CEM, 1979).SOFT START MECHANISM EV ALUATION CRITERIONWhat 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 (Llewellyn and Sudarshan, 1978).Belt Drive SystemFor 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 (Zur, 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 AttributesSize.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 over speeding on regeneration, or overheating with shortened motor life (Lodi, etal., 1978).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 withoptimized 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 range 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 debating or over sizing of system components. There is a direct relationship between thermal rating for repeated 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 toregulate 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 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 costof training onsite personnel, or the cost of downtime as a result of insufficient training.Multiple Drives.A simple belt is often driven by one drive pulley. Multiple, independent pulleys drive some more complex belts. These pulleys may be near each other, or at different belt locations. Multiple drives allow the belt designer to increase the driven horsepower, while maintaining or reducing belt fabric tensions. Multiple drives require a drive starting and running system that allows for coordination between drives. Multiple drives of different sizes or different belt wrap angles may require a load proportion scheme (load sharing). Load sharing requires one of the drives to operate at a lower torque rating during starting, or also during running conditions. Will the multiple drive belt system operate with one or more prime movers out of service? Multiple drives at different locations will require a distributed control system (Gallina, 1991; Sur, 1987).Conveyor Jam.It is possible for a running belt conveyor to encounter a mechanical jam of the belt fabric. The drive system will continue to impart torque to the fabric up to the slip of the fabric on the drive pulley. Different drives vary in the application of breakdown torque to the stalled machine. It is important for the drive designer to examine the rotating inertia in the drive system. The prime mover motor rotor and all other rotating parts may contribute significant kinetic energy to the stalled belt. The drive response to the stall and the application of the torque limit may vary.Control System.Each drive system will require a base case permissive control system for starting and running supervision. Most belt drive systems today use some form of computer control. The computer control systems all depend on field sensors for measurement and reporting of drive parameters. The belt drive designer must determine the minimum required number and location of the field devices for adequate control. The drive control system will require power switchgear and control switchgear with provisions for "lockout" for conveyor maintenance and service. Lockout applies to sources of electrical, hydraulic, pneumatic, and gravity energy.SOFT START METHODS OVERVIEWThe system approach will group the electrical prime mover with control, the high and low speed couplings, the speed reducer, and the drive pulley for examination. The belt conveyor will require a force to initiate movement, termed breakaway torque. In movement, the conveyor willrequire torque to support existing motion and torque to support acceleration to running speed within the time and thermal limits imposed by the system. The resultant acceleration is proportional to the applied force divided by the mass in the system according to Newton's second law, where the mass is the system equivalent weight, or external inertia, divided by the force of gravity. More commonly, the belt designer will calculate the Wk, or the weight of the system times the square of the radius of gyration. It is important that the designer add the drive system external inertia to the belt system inertia in order to view total system inertia. System inertias are modeled at the rotating speed of the electrical prime mover, or at the linear speed of the belt fabric. All system external inertias must be referred to a common base (Harper, 1960).中文翻译煤矿输送带软启动机制的比较Michael L. Nave, P.E.CONSOL Inc.1800 Washington Road Pittsburgh, PA 15241在采矿业，带式输送机是运送散装材料方面的一个重要方法。
绳架吊挂式带式输送机设计-外文翻译
绳架吊挂式带式输送机设计ABSTRACTA machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term "mechanical design" is used in a broader sense than "machine design" to include their design. the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers.KEY WORDS Mechanical, Design mechanisms,Design Process1 The Design ProcessDesigning starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly.In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of anidea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems.Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) don't understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials.Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity.May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding.Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal.2 Some Rules for DesignIn this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical, and durable products.To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst.1. A creative use of need of physical properties and control process.2. Recognize functional loads and their significance.3. Anticipate unintentional loads.4. Devise more favorable loading conditions.5. Provide for favorable stress distribution and stiffness with minimum weight.6. Use basic equations to proportion and optimize dimensions.7. Choose materials for a combination of properties.8. Select carefully, stock and integral components.9. Modify a functional design to fit the manufacturing process and reduce cost.10. Provide for accurate location and noninterference of parts in assembly.Machinery design covers the following contents.1. Provides an introduction to the design process , problem formulation ,safety factors.2. Reviews the material properties and static and dynamic loading analysis ,Including beam , vibration and impact loading.3. Reviews the fundamentals of stress and defection analysis.4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design of rotation machinery.5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue.6. Investigates shaft design using the fatigue-analysis techniques.7. Discusses fluid-film and rolling-element bearing theory and application8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing.9. Discusses spring design including compression ,extension and torsion springs.10. Deals with screws and fasteners including power screw and preload fasteners.11. Introduces the design and specification of disk and drum clutches and brakes.3 Machine DesignThe complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations.Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked.The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aideddesign (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on.If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of productMust regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience,because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after confirmation new idea.摘要机器是由机械装置和其它组件组成的。
带式输送机几种软起动方式的比较——毕业设计外文文献翻译、中英文翻译
外文原文：A Comparison of Soft Start Mechanisms for Mining Belt Conveyors1800 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.INTRODUCTIONThe 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 limits. Smooth starting of the conveyor can be accomplished by the use of drive torque control equipment, either mechanical or electrical, or acombination of the two (CEM, 1979).SOFT START MECHANISM EV ALUATION CRITERIONWhat 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).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 perhour 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 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 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 LOGICEach 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 controlsystem 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 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 shutdothe 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 methodinvolves 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 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.CONCLUSIONThe 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, theuse of synthesized waveform electronic drives will expand.译文：煤矿业带式输送机几种软起动方式的比较统一公司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。
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出自: The South African Institute of Materials Handling有关带式输送机驱动装置设计的一些研究J.H. Rall 理工学硕士,汉森变速器（控股）有限公司董事P. Staples 理工学硕士,输送机知识与信息科技（控股）有限公司（CKIT）董事、总经理摘要：这是是一篇关于探讨运送大量颗粒物质的动力和平板橡胶输送带之间的驱动装置的综述。
它关注的是大批量的物料输送，而不是像喂料或计量输送带，大倾角式输送机等特殊情况。
它主要研究电机联轴器和驱动滚筒之间的减速器，带速，轴承寿命，使用因数，制动器和逆止器等。
1.概述地球原材料的消耗越来越多，那就需要很快地将这些材料从一个地方转移到使用它的地方，而且要通过一定的工艺来运输这些物料并且要在最短的时间内处置废物。
许多物料输送的方法是从轮手推车送到自卸卡车或接送的车辆上，或是依靠一定的空气流在空气导管中进行散料输送。
这种输送方式中，在限制成本的前提下，在可靠的长距离的物料输送中带式输送机发挥了非常重要的作用。
每一种物料输送都有其优点和缺点。
带式输送机的问题之一是，输送带柔软易降解，特别是在装货和卸货的时候。
如果维持整体尺寸是很重要的话，那么照目前的技术来说这在复杂的输送系统中是很困难。
输送系统已变得越来越大，越来越复杂，驱动系统也已经历一个演进过程而且会继续演进下去。
大带要求很大的驱动力。
不仅需要更大的独立驱动装置，同时也需要多驱动装置比如一个带需要4个各1000KW功率的驱动器。
完整驱动装置中轴的安装是另一个变化，它要求更紧凑重量更轻的驱动装置。
这往往倾向于在输送带和硬齿面齿轮旁边配置一个直角驱动器来减小驱动器的尺寸和质量。
2. 传动比与带速根据待输送物料的数量，规模，输送距离和其特点的不同决定了带的吸收功率，宽度，拉伸要求和厚度等。
大部分的传送带带速范围在2～6m/s，并且由带允许的弯曲半径决定了托辊的直径。
大型传送带的托辊直径在0.8～1.5m之间，托辊速度在50～125rpm之间。
假设使用4极电机，这能提供12:1～30:1之间需要的减速比。
大部分的齿轮制造商不会采用过高的传动比，每级传动比不超过5:1，这意味着将会是2～3级减速。
（除小功率的蜗杆减速器或是扭矩臂和V带驱动器可能会使用）。
有一种误解以为减速器使用6或8极电机可以降低成本，但即使是8极电极能有更高的速度，且每级减速比超过6:1，这样仍然需要2级传动。
大部分变速器的成本与低速轴的扭矩有关系。
因此，只要确定了这一点，除了使用了4极电机以外使用其他任何电机相比之下都是没有任何经济优势可言的。
由于受到规模和数量的限制，一般对电机制造商来说提供的4极电机的价格最低。
因此作为选择电机的一条原则，为了达到要求的传动轴速度，4极电机是最佳选择了。
电动机使用球轴承和滚子轴承的一些制造商喜欢6极甚至8极的转速，能给电机提供超过1000千瓦的功率。
3.1 选择单个或多个驱动器在计算出驱动皮带所需功率和皮带张力和包角之后就可决定就带是否应装有一个或多个驱动器。
这一决定往往受安装在工厂的数倍于经常使用的小驱动器等设备的影响。
驱动器的大小也可能由最近可用的标准电动机决定。
如果一个驱动器离主要动力源有相当的距离，那么就要用一根长的电缆来连接电机和驱动器。
这样一来，在选择我们使用的电机的数量和尺寸时电缆尺寸和变压器的成本就可能发挥一个很重要的作用。
随着电机的启动，电动机的峰值电流可能是6相满载电流。
一个电机或一组电机的运行电流与最后一个电机启动时的启动电流之间的联系对驱动器的选择会有很强的影响。
3.2 低速轴的连接从减速器到皮带轮轴的传动一种是通过与安装在构架旁边的基础部件上的驱动装置的“弹性”耦合来实现，一种是通过挂在带轮轴上的驱动装置的轴来实现。
驱动装置可以安装空心轴，通过摩擦锁合原理来驱动或是安装实心轴用一个刚性联轴器将其与输送机轴连接起来以实现驱动。
附件中给出了一些典型的附属装置草图。
（见附录A ）。
4.1 起动方法﹑驱动器的大小和保护装置的选择在启动传送带时，通常涉及到一个需要加速的相当大的质量。
为了缩短电机达到启动电流的时间，需要在减速器和驱动电机之间安装一个“滑动联轴器”。
另外，滑环电动机的使用，实现了通过控制电机的峰值电流以实现快速且柔性启动。
功率10kW以下的小带直接在线器启动采用直接耦合是很正常的，但对于100千瓦以下的带来说采用“滑动联轴器”是最常见的，而且可能是最简单和成本效益最大的。
采用较大的驱动器来获得需要的功率会持续的增加成本，在这种情况下滑环电机就可能引起了人们的注意，因为它能预防用电高峰期，特别是在最高电力需求需要支出大量电费的时候。
市场上有很多种与D.O.L.启动机配套使用的滑动联轴器，但对于较大的输送带来说多数使用液体耦合器，无论是连续牵引或是延迟填补牵引或是可控填补填补牵引（杓子式）。
流力耦合器总是会做少量的“滑动”以帮助多个驱动器共担负载，并且提供了精确调整过的耦合“填补”。
一般来说，每个耦合器都略有各自不同的特点，如果正确调整分担载荷，在满载条件下将有可能比轻载条件下不适当的分担载荷更好。
电机的特点也各不相同，这有助于多个驱动器分担负荷。
驱动系统通常都是每带最多4个电机，但只用很少的会用更多的电机。
4.2 电动机起动（D.O.L.与液力偶合器）多个驱动器启动的一般做法是先启动次级驱动器电机3～5秒钟后在启动另一个主级电机，持续5～10秒钟后启动下一个主级电机。
然而，在实践中观察到启动开始后和理想状态有一个时间延迟。
一个非常常见的现象是观察到次级驱动电机由于保守耦合的选择，启动电流有所下降，但很快又开始上升，由于延迟填补耦合增加了它的滑动力矩，而带依然平稳。
如果主级驱动器是在耦合扭矩大幅度增加之前的正确时间启动的，带就会在过低电流状态下带速增加。
联轴器的相对滑移影响到它的扭矩和电机电流，而且很快带就可以启动了，峰值电流很快也将下降。
在杓子式液力偶合器中所有电机都很快成功的启动然后所有联轴器开始缓慢填补。
滑环电动机也采用类似的的方式启动。
这两种方法无疑对皮带，皮带轮是有利的方式。
采用杓子式液力偶合器或滑环电机有可能使较小型电机的使用更安全和开关装置维修成本的节省。
4.3 其他驱动器方法如果要求输送率变化的，那么直流驱动器可以当作鼠笼电动机来实现变频控制。
另一种方法是用水文静态驱动器，但大功率驱动器的运行和维护费用上很可能会高于采用SC电机液力偶合驱动器和或滑环电动机。
4.4 带保护带保护是为了防止超载和失控。
其做法通常是通过皮带下方的托辊驱动的离心开关来实现的。
然而，这并不是现在使用的非常灵敏和最尖端的方法。
一种恰当的方法是在驱动变速箱低速轴上安装一个脉冲发生器，皮带驱动的托辊上装上类似的脉冲发生器。
监测器能不断的检测脉冲频率，如果输送带跑偏的话它就会给出警报或直接使带停下来。
通过使用监测器来控制滑环电动机的启动能将带的跑偏滑动控制在最低限度内。
监测器可控制转子电阻继而控制起动转矩。
5. 带式输送机制动5.1 正向制动一般说来，摩擦会降低皮带正常前进的速度并增加负载使其在相对较短的时间内停止。
停车时间的长短主要取决于卸料结束条件。
如果一个带给另一个带送料是，平稳的条件，转载仓的大小和带的布局可能会需要一个制动带的其他方法而不是靠正常的摩擦。
一般来说向下卸料或是向上输送的带都需要制动。
如果一个输送带输送部分比输送机其它部分长很多的话，输送斜槽就可会超载甚至可能是遭到破坏，但这种情况很少出现。
先初步根据输送带的布局（见附录B ）在变速箱高速轴上装制动器，可以看到，当又载荷的情况下停止的时候载荷的惯性往往会依靠重力拉紧和释放驱动器和前部带轮之间带的张紧力，甚至带还可能会松弛。
反转时驱动器因制动器作用而不动，但负载会在重力的作用下使带加速。
而当驱动器和头部滚筒张紧时，就会使因负载而加速的带由于长距离输送之间的摩擦力而减缓下来。
在这种根据负载突然停止的时候驱动器会受到剧烈冲击。
在这种情况下，制动不仅是不必要的，而且是极不可取的。
安装在卸料带的制动器将再次释放驱动器和头部滚筒之间的张紧力，但这往往会释放正在运行（或停止）的带轮的张力，并使得带有滑动。
这对皮带和带轮有害，而且也是很危险的。
制动带正确的方法像是这样的：在带尾部滚筒或反转时的其它滚筒上采取行动。
另一个制动器有时会用到的方法有时用一个移动堆垛机来制动皮带，以减少带的刮伤；带固定的时候堆垛机应能够移动。
但在尾部滚筒上仍然要装一个制动器，在驱动器或输送机头部安装一个钳制器。
附件：FROM : The South African Institute of Materials Handling BELT CONVEYOR DRIVES - A CONSIDERATION OFSOME DESIGN ASPECTSJ.H. Rall Pr.Eng., BSc Eng., MSAIME Hansen Transmissions(Pty) ltdP. Staples Pr.Eng BSc, MSAIMEManaging Director Conveyor Knowledge and InformationTechnology (Pty)Ltd (CKIT)Summary:This is a short review of part of the link between the electric power grid and flat rubber covered belts used for transporting large volumes of granular material. It is concerned with high volume material conveying and not with special cases such as feed or metering conveyors, steep inclined conveyors etc. It considers mainly the speed reducer between motor coupling and drive pulley, ratings, bearing life, service factors, stopping and anti-runback devices1.GeneralThe ever increasing rate of consumption of earth's raw materials has brought with it a need for faster movement of these material from the point of extractionto the point of process or usage and transporting these materials through the process plant and disposing of the waste in the shortest possible time. Many methods of material handling are employed from wheel barrows to dump trucksor shuttle cars, to pneumatic ducts carrying pulverised particles in an air stream.In this line of movement, belt conveyors play a very important part in the reliable carrying of material over long distances at a competitive cost.Each method of material conveying has its advantages and disadvantages. Oneof the problems with belt conveyors is that soft friable material can be degraded, particularly in loading and unloading. If the maintenance of lump size is important, this can present difficulties on a complicated conveyor system.Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to do so.Bigger belts require more power and has brought the need for larger individual drives as well as multiple drives such as 4 drives of 1000 kW each on one belt. Shaft mounting of the complete drive unit is another change which has brought with it the requirement for more compact and lighter drive units. This tends to favor a right angle drive configuration with the motor next to the belt and hardened gears to reduce the dimensions and mass of the drive.2. Drive Ratio and Belt speedsDepending on the quantity, size, distance and characteristics of the material to be conveyed, the absorbed power, width, tensile requirements and top cover thickness of the belt will be decided.Large volume conveyor belts run in the range of 2 to 6 metre/second and the allowable bend radius of the belt determines pulley diameters which for large belts is of the order of 0,8 to 1,5 m giving pulley speeds between 50 and 125 rpm. Assuming that 4 pole motors are used, this gives a reduction ratio required between 12:1 and 30:1.Most modern gear manufacturers do not use a higher ratio per stage than 5:1, which means that speed reducers will be either 2 or 3 stage reduction. (Except for small powers where worm reducers, or torque arms and V belt drives may be used).There is a misconception that one can reduce the cost of the gear-speed reducer byusing a 6 or 8 pole motor, but even an 8 pole motor on the higher speeds would require a reduction above 6:1and a 2 stage unit would still be required. The bulk of the cost of a gearbox is related to the low speed shaft torque and therefore having determined this, there is generally no economic advantage at all in using anything but a 4 pole motor. The motor manufacturers, because of size and volume, generally supply 4 pole motors at the lowest price, and as a rule therefore, a 4 pole motor is the best choice with a gearbox of the appropriate ratio to arrive at the desired conveyor shaft speed.Where ball and roller bearings are used in the electric motors some manufacturers prefer 6 pole or even 8 pole speeds for motors over 1000 kW.3.1. Choice of Single or Multiple DriveHaving calculated the power required to drive the belt and having considered the belt tension and angle of contact, a decision can be taken on whether the belt should be fitted with single or multiple drive.This decision is often influenced by other equipment installed in a plant and multiples of other smaller drives are often used. Drive size may also be determined by the nearest standard motor available. Where a drive point is situated some considerable distance from the main power source, a long cable may be involved to supply electric power to the drive. In this case, the cable size and cost of transformers may play an important part in the selection of number and size of motors used. With direct on line starting, the peak current the motor will draw is likely to be of the order of 6 x full load current and the combination of running current of a motor or group of motors with the starting current of the last motor to start will have a strong influence on the drive choice.3.2. Method of Low Speed Shaft ConnectionsDrive from the reducer to the belt pulley shaft is either by "flexible" coupling from adrive pack mounted on a foundation next to the structure or by shaft mounted drive unit hanging on the pulley shaft. When shaft mounted, the drive unit can be either hollow shaft, driving through a friction locking element or solid shaft attached by a rigid coupling to the conveyor shaft. Some typical attachments are shown in the sketches. (See appendix A).4.1. Choice of Starting method, drive size and ProtectionDuring start up of conveyor belts, a considerable mass is usually involved which requires acceleration, and to reduce the length of time that the motor draws starting current, a "slip coupling" is fitted between the drive motor and speed reducer. Alternatively,slip ring motors are used to achieve a quick but gentle start up with control of the peak current. On small belts below 10kW direct on line starting directly coupled is quite normal and on belts, say below 100 kW D.O.L. starting with "slip" couplings is most common, and probably the simplest and most cost effective. On larger drives with power at its present continuously increasing cost, slip ring motors may be attractive, due to the prevention of the peak, particularly where maximum demand plays a part in the electricity tariff.There is a multitude of slip couplings on the market for use with D.O.L. start motors, but for larger belts the majority in use are liquid type couplings, either straight traction or traction with delayed fill or controllable fill (scoop type). A fluid coupling will always "slip" a small amount and will help multiple drives to share load, provided the coupling "fill" has been carefully adjusted. As a rule, each coupling has a slightly different characteristic and if adjusted to share load correctly under full load conditions will more than likely not share properly under light load conditions. Motor characteristics also vary a little and can also contribute to poor load sharing on multiple drives. Drive systems commonly go up to 4 motors per belt, but rarely more.4.2. Motor Starting: (D.O.L. with fluid coupling)On multiple drives accepted practice is to start the motor on the secondary drive firstand say 3-5 seconds later one of the primary drive motors and then the next primary motor say 5-10 seconds later.In practice, however, the observed starting procedures and delay times vary a great deal. A very common sight is to see the secondary drive motor running and due to conservative coupling selection, the starting current drops somewhat, but starts rising quickly again due to the delayed fill coupling increasing it's slip torque, while the belt remains stationary. If a primary drive is started at the correct time before the coupling torque has increased too far, the belt is brought into motion much quicker with a lower overall current. The relative slip of the coupling affects it's torque and so the motor current, and the sooner the belt can be moved, the sooner the current peaks will drop.In the case of scoop controlled fluid couplings all motors are started in quick succession and then all couplings filled slowly. A similar procedure is followed with slip ring motors and these two methods are undoubtedly the kindest to the belt, pulley and lagging etc.The choice of scoop type fluid couplings or slip ring motors is likely to lead to the use of smaller motors with safety and possible savings on switch gear maintenance.4.3. Other Drive MethodsWhere a variable conveying rate is required, D.C. drives can be used as well as squirrel cage motors with frequency control. Another method is by hydro-static drive; again ideal for variable speed, but overall running and maintenance costson big powers are likely to be higher than a fluid coupling drive, with S.C. motoror slip ring motor.4.4. Belt ProtectionBelt protection against overload and stalling is commonly done by a centrifugal switch driven by a roller on the underside of the belt. This, however, is not very sensitive and more sophisticated methods are now used.One method consists of fitting a pulse generator to the drive gearbox low speed shaft and similar pulse generator to a roller driven by the belt. A monitoring unit compares the pulse frequencies continuously and if they go outside set limits, an alarm is given or the belt stopped. On start up, belt slip can be kept to a minimum by using the monitoring unit to control the start up on slipring motors. The monitoring unit can control the rotor resistance and so the starting torque. Alternatively, the "fill" of a variable fill fluid coupling can be controlled by the comparitor.5. Stopping a Belt Conveyor5.1. Forward stoppingAs a general rule, friction will reduce the normal forward speed of the belt and load and bring it to rest in a relatively short time. The allowable time for stopping depends mainly on the discharge end conditions. Where one belt feeds onto another, tripping conditions, transfer bunker size and belt layout may indicate a need for a belt to be slowed down by other methods than normal friction.On a downhill section of a conveyor discharging onto a level or uphill belt is generally the place where braking is required. If one belt runs on longer than the rest of a system of conveyors, bunkers or transfer chutes can be overloaded and may even be a hazard, but this is generally a very rare condition.Considering a conveyor layout as per sketch (see appendix B) fitted with a brake on the gearbox high speed shaft, it can be seen that when stopped under load the inertiaof the load would tend to pick up the gravity tensioner and release the tension in the belt between drive and head pulley and may even go slack by the time the load comes to rest. The load assisted by the gravity take up would then accelerate the belt in the return direction while the drives are stationery with brakes on. When the belt between drive and head pulley becomes tight it has to retard the load in a fraction of the distance in which it had been accelerated. Under this sudden stopping of the load the drive is subjected to heavy shock. In this case, a brake is not only unnecessary, but highly undesirable.A brake fitted on a downhill belt drive would again release tension between drive and head pulley and pick up the take up, but this would tend to release tension on the driving (or stopping) pulleys and allow the belt to slip. This can damage the belt and pulley lagging and can also be dangerous. The proper method of stopping a belt like this is on the tail pulley or other pulley on the return belt after it leaves the take up. Another application where brakes are sometimes used is on belts running through a mobile stacker, to reduce the risk of the belt snagging; should the stacker be moved while the belt is stationary. Here again a brake would be fitted to the tail pulley and a holdback to the drive or head.。