32-5t电动双梁桥式起重机小车运行机构设计

喜欢这套资料就充值下载吧。资源目录里展示的都可在线预览哦。下载后都有，请放心下载，文件全都包含在内，有疑问咨询QQ:414951605 或 1304139763 辽宁科技大学本科生毕业论文 第16页 Digital Drive Crane Hoist Conversion While working on the bridge of a crane, I remember feeling the intense heat of the speed reduction Resistors. I looked over the prints and tried to figure out how to reduce this energy loss. As I understood, heat is the product of energy lost (). I was new to crane maintenance in 1990 and, having an electrical/electronic background, Crane panel manufacturers desired a novel method of crane control that combines new technology with some of the oldest. The new crane panel resulted in lower costs, increased productivity and reduced wear on components, as well as energy savings. I believed new technology existed. Several of the newer devices needed alternating current input. SCRs, VFDs and PMWs were becoming common acronyms in newer plants. The possibility of upgrading our pre-existing 250 VDC distribution was cost-prohibitive, Various transistors could run DC, but not at the ampere demands we needed. With crane panel replacement under consideration, we challenged our panel suppliers to develop new crane control technology Digital Hoist Conversion Severstal North America Inc. is an integrated steel mill dating back to 1917, when Henry Ford built it to supply his Ford Motor Co. auto manufacturing enterprise. It was operated as Ford Steel Division ur~ti11982, when it became Rouge Steel Co. In 2004, OAt Severstal Steel purchased the assets of Rouge Industries and Rouge Steel. Figure1.A digital drive controller was installed Figure2. Preliminary setup of DDC hoist panel on this 135-ton-capacity slab-handling crane The market price for steel was flat in the early part of the new millennium, forcing departmental groups to look for cost-saving improvements. One improvement was the installation of a new type of digital electronic control panel in 2003. This panel represented the introduction of DC electronic crane control to Rouge Steel and the largest duplex crane hoist controller (dual 200-hp) of its type in North America. The original panels were built on a P&H 135-ton slab-handling crane having standard DC hoisting contactor controls. They were industrial and functional, designed to handle the loads of this crane in 1972. The loads are greater now with heavier slabs, runing the crane at maximum limits and higher production rates. This caused premature equipment failures and production down-time. With three aging cranes in this bay, maintenance costs were rising to new highs. Those involved in maintenance were finding that distributors and manufactures were downsizing or had gone out of business, making replacement parts costly or obsolete. The market drivers of today are forcing the change to newer technologies Figure3. Digital panel installed on crane trolley deck Figure4.Prewired resistors reduced start-up time A novel design approach was asked of the crane panel manufactures. They replied with a proposed partnership and an effort to add some of the newest technology to the oldest methods of crane controls. The result was high-current transistor switching with a 250 VDC input. The design was well-thought-out and included integrating the original motors, limits, switches and wiring. Now speeds are controlled by sending the motors only enough current to safely lift and lower the load. The motors are soft stopped (reverse plugged) before the brakes close. This saves wear on components, reduces costs and increases productivity. Without the need for reduction resistors, there is no energy wasted, maximizing the energy savings. The panel installation of the SY-4 crane was completed in 2003 and is still running. The results are smoother movements with little energy loss (heat). The new panels were designed for installation on the trolley deck, as opposed to the bridge deck.. This aids in troubleshooting and reduces excessive wiring mainly at the weak point of the cable powertrack.. This allowed the time and ability to perform all setup work during mini-downturns without disabling the original hoist. The original panel was left in place as a backup, as failures could not be predicted. To date, the fail-safe panel has not been required. The panels were pre-wired and pre-tested prior to crane installation, further reducing crane downtime. When the transfer day came, only the master switch, motors and limit leads needed to be rerouted to the new system. On-the-job tuning and monitoring were vital for the first couple of days. It was important to have crane operators involved for that “personal feel” and to obtain their buy-in to the project, to increase awareness and productivity. No-load and full-load current tests were run with great results. An aded benefit to this control is the electrical current savings. Without reductin resistors for speed points, and with the added benefit of power produced when regenerative lowering, this single crane installation saves more than ＄25000 in electricity annually. This can be a very important consideration if substation power is near critical usage levels. The demand this system imposes is much less than a similar contactor system. With energy costs on the rise, this is a concern for every project considered. Figure 5 indicates an example of electrical current savings potential by comparing contactor panel loads(top) to digital drive loads(bottom). How it works in the circuit is not unique. The insulated gate bipolar transistor(IGBT) takes the place of the contactors and acceleration resistors. As the master switch is selected for greater speed, the circuitry triggers the transistor at a frequency(pulse width modulated) that allows current to flow through the IGBT. The current circulates in the standard series armature and series field along with the series brake. The longer the input is turned on, the higher the output average voltage (Figure 6). The higher the voltage, the higher the horsepower produced. This system can provide high torque with low currents(heat) as the result of motor regenerative properties. High speed with no load can also be accomplished. Much of this could not be achieved with the original panels. Figure5.Example of energy saved during lowering sequence. The difference is noticed when the IGBT is in its off cycle(Figure 7). In this instance, the motor acts as a generator, producing circulating currents through the flyback diode and maintaining self-induced motor currents. This effect reduces ripple and provides current that was not provided by the original power source. The reduction of current loads on system feeders and hardware further adds to the total savings package. The following items are important considerations when determining if this system will work with an application. IGBTs are the newest part of the design that makes this panel work with 250 volts DC. They combine the advantages of the bipolar transistor(high voltage and current) with the advantages of the metal oxide semiconductor field effect transistor(MOSFET)(low power consumtion and high switching). IGBTs are semiconductors that combine a high voltage and high current bipolar junction transistor(BJT) with a low-power and fast-switching MOSFET. Consequently, IGBTs provide faster speeds and better drive and output characteristics than power transistors and offer higher current capabilities than equivalent high-powered transistors. Figure6.Hoist current flow when the IGBT is on Figure7.Hoist continuing motor current flow when the IGBT is off. Heat sinking, including consideration of air temperature and air flow, is essential to the proper operation of any solid-state reply. It is necessary to rovide an effective means of removing heat from the IGBT. The importance of using a proper heat sink cannot be overstressed, since it directly affects the maximum usable load current and maximum allowable ambient temperature. Up to 90 percent of the problems with transistors are directly related to heat. Lack of attention to this detail can result in improper switching(lockup) or even total destruction of the IGBT. If the device ever reaches an internal temperature of 105℃, it will be permanently destroyed. One of the problems encountered at Severstal NA was program temperature cutbacks due to excessive heating. When electrical current cutback does not control the drive, it will stop on software limits. Transistors develop heat as a result of a forward voltage drop through the junction of the IGBT. Beyond this point, heat will cause a reduction(software cutback) of the load current that can be handled. If the demand is too great, the program is designed to shut down. Care must be taken when mounting solid-state relays(SSRs) in a confined area. SSRs should be mounted on individual heat sinks whenever possible. SSRs should never be operated without proper heat sinking or in free air, as they will thermally self-destruct under load. A simple way to monitor temperature is to slip a thermocouple under a mounting screw. If the base temperature does not exceed 45℃, the SSR is operating at its optimal level. Remember that the heatsink removes the heat from the SSR and transfers that heat to the air in the electrical enclosure. In turn, this air must circulate and transfer its heat to the outside ambient. Vents and forced ventilation are good ways to accomplish this. Semiconductor fuses are the only reliable way to protect SSRs. They are also referred to as current-limiting fuses, providing extremely fast opening while restricting let-through current far below the fault current that could destroy the semiconductor. This type of fuse tends to be expensive, but cheap by comparison to the damage that could occur, providing a means of fully protecting SSRs against high current overloads. An fuse rating is useful in aiding in the proper design of SSR fusing. This rating is the benchmark for an SSR's ability to handle a shorted output condition. Devices such as circuit breakers and slow blowfuses cannot react quickly enough to protect the SSR in a shorted condition and are not recommended. Every SSR has an rating. The idea is to select a fuse matching the capability of the solid-state relay for the same duration. Figure8.IGBT and components mounted on heat Figure9.External mounted fans removed IGBT heat Figure10. Panel fans removed internal heat buildup Figure11. Semiconductor fuses provide the best protection for solid-state relays Motor switching and dynamic loads, such as motors and solenoids, can create special problems for SSPs. High initial surge current is drawn because its star t-up impedance is usually very low. As a motor rotates, it develops a counter electromotive force (CEMF) that resists the flow of currenL This CEMF can also add to the applied line voltage and create over-voltage conditions during turn-off and regenerative times. It should be noted that over-voltage caused by inductive voltage doubling or CEMF from the motor cannot be effectively dealt with by adding voltage-transient suppressors. Suppressors such as metal oxide varistors (MOVs) are typically designed for brief high-voltage spikes and may be destroyed by sustained hlgh-energy conduction. Voltage dump resistors may be needed in extreme cases and should be engineered to meet a system's demand, It is therefore important that SSRa are chosen to withstand the highest expected sustained voltage. Problems encountered while running the200-hp dual drive were few hut worth mentioning. The program allows for setdng many variables (i.e., speed, currents, brake-open voltage). Most of these are detrimental to the drive or motor if set incorrectly. Although staying within the drive specifications is safe, this may not produce the desired actions. Ambient temperatures must also be considered, since most useful application are near higher-temperature areas. Following are several problems(and solutions) observed during installation and trials: l Problem 1:The first problem presented itself when applying excessive brake-open curent. The direction contactors were flashed and pitted. Also, the emergency brake contactor appears bluish from high heat. Reducing brake-open current and power-on time to a shorter duration solved the problem. l Problem 2:Hall effect transistors and IGBT were thought to be faulty parts and/or wiring, but this could not be duplicated. Many suspect parts were replaced, but it was determined that internal panel ambient temperature was the problem. This was solved with cooling fans on the doors and on the IGBT cooling fins. l Problem 3:Temperature cutbacks usually led to errors. It was found that a new crane operator did not like operating the hoist at full speed. Longer run time and higher IGBT cycles caused unnecessary heating in panels. Reducing field current settings eased this problem. This increased the lowering speeds but greatly reduced the IGBT voltage drop, in turn reducing its heat dissipation. Cooling fans eliminated the problem. l Problem 4:All power must be disconnected from the line because all lines feed from a common bus capacitive filtering system. This means that the typical way of “pulling motor disconnect and running the controls only” to troubleshoot does not work. The panel diagnostics and troubleshooting information provided is very helpful. l Problem 5:Lack of electronic knowledge by the electricians is a concern. When production downtime is critical, the time to troubleshoot is a high-priced commodity. This ultimately puts pressure on the electricians, causing frustration. The solutions was to ensure that the crew is involved Mth project design and installation. Training is vital. If the maintenance team is nat up to speed with the technology, failure is probable. Two training classes were held for all electrical team members. After one year, the actual materials maintenance and labor savings were calculated, with a payback of 6.2 months. Cost savings and efficiency gains were greater than expected. This led the way to the next drive conversion, which was scheduled for 2006. With a cooperative effort by salespersons, manufacturers, engineers and end-users, Severstal NA vastly improved its ability to compete successfully. Acknowledgments The author would like to acknowledge the efforts of former general supervisor Fred Schwartz and the crew at Severstal North America. Without their help, the project may never have gotten this far. References 1. Creech, R., 'Energy Savings -- DC Digital and DC Contactor Hoist Control System," Iron ~ Steel Technotogg, May 2005, pp. 225-228. 2. http://ray.eeel.nist.gov/modval/database/contents/reports/igbt.html 3. http://web.ece.umr.edu/computing/unix/software/matlab/toolbox/powersys/igbt.html 4. http://www.fujisemiconductor.com/old_pdf/app_ notes/r_ipm.pdf 5. http://www.mathworks.com/access/helpdesk_r13/help/toolbox/physmod/powersys/igbt.html 数字机起重机提升转换 虽然工作在桥上的吊车，我记得感觉酷热的速度减少电阻.我看着图纸，并试图弄清楚如何减少这种能源损失.正如我的理解一样，热是产品的能源损失（ ） 。我是新来起重机维修工于1990年，并在电气/电子背景下，我认为新技术是存在的.一些较新的设备需要交流电输送.在新工厂，SCRs ， VFDs andPMWs已成为常用缩写词。在新的可能性下，提升我们的预先分配现有的250伏直流电是成本过高.各种晶体管可以运行直流，但不能以安培的要求，.现在起重机小组正在考虑向我们的面板供应商提出制定新的起重机控制技术。 起重机面板制造商设计了一个新的起重机控制方法，那就是把新技术和最老的技术结合起来。这个新的起重机面板导致了降低成本，提高生产力和减少磨损的部件，以及节约能源的效果。 数字提升转换 韦尔北美公司是一家综合钢厂可以追溯到1917年，当亨利福特建立它提供了福特汽车公司生产企业. 在1982年之前，这是作为福特钢司，之后改名为高棉钢公司。在2004年，俄罗斯谢韦尔钢收购了高棉钢铁工业和高棉钢公司。 在新的千年年初，钢铁的市场价格持平，迫使部门团体寻求节省成本的改进。在2003年，一个改进的方法是安装一种新型的数字式电子控制面板，这个小组代表介绍，在北美，直流电子起重机控制高棉最大的钢铁和全双工起重机吊重机控制器（双200马力）的类型。 图1.数字硬盘控制器被安装在这台有 图2.初步安装DDC的提升小组 135吨板坯处理能力的起重机上 原来的面板上建立了一个P&H公司135吨板坯处理起重机在吊装标准直流接触器控制。它们的工业功能被设计用于处理负载的这台于1972生产的起重机。在保证最高限额和更高的生产速度之下，运行起重机的负载更大了就好比加了巨大的石板。这就造成早产和生产设备故障停机时间加大。三老化起重机在这湾，维修费用上升到新高。那些参与维修的人发现，分销商和制造商缩编或已停业，使备件昂贵或过时。市场驱动的今天，迫使改变新技术。 起重机面板制造商被要求需要一种新的设计方法。他们回应在最基本的起重机控制上努力增加一些最新的技术。其结果是高电流晶体管开关的250伏直流电输入。设计是经过深思熟虑的，其中包括整合原汽车，限制，交换机和拧。现在速度控制发送只够目前的汽车安全升降机及降低负荷。电机软停止（反向插入）前刹车密切。这样可以节省的磨损部件，降低成本和提高生产效率。而不需要减少电阻，没有能源浪费，最大限度地节约能源。小组安装系统- 4起重机于2003年完成，目前仍在运行。结果表明，几乎没有顺畅流动的能量损失（热）。 图3.数字面板安装在起重机小车甲板上 图4.预置电阻减少启动时间 新的面板设计为安装在甲板上的小车，而不是桥面。这个故障排除和减少过多的电线主要是在于电缆的薄弱。在稍微衰退而停用原来的起重机，在这允许的时间和能力内来执行所有的安装工作。原来的面板留在地方作为备用，失败是无法预测的。迄今为止，面板没有达到万无一失要求。 该小组的前有线和预先测试前，起重机安装，进一步降低起重机停机。当一天的转让中，只有总开关，汽车和限制导致需要转移至新系统。在职调整和监测至关重要的第一几天。这是非常重要的吊机操作员参与的“个人感觉” ，并获得他们的买进该项目，以提高认识和生产力。空载和满负荷运行试验，目前取得极大的结果。 一个附加的好处是这个控制电流储蓄。没有电阻减少的速度点和再生降低时，功率产生的附加的好处，这种单一的起重机安装每年节省超过25000美元的电费。这是一个非常重要的事情是附近变电站电力使用水平的关键。在实行这一制度的需求远低于类似的联系人制度。随着能源成本上升，图5显示的一个例子电流储蓄潜力比较接触小组负载（顶部）到数字驱动负载（下）。 如何运作的电路并不是独一无二的。绝缘栅双极晶体管（ IGBT ）取代电流接触器和加速度电阻。作为主开关是选择更大的速度，晶体管电路触发的频率（ 脉宽调制） ，使电流流过IGBT的。目前流通中的标准系列电枢和一系列领域随着一系列制动。投入的时间越长，，输出更高的平均电压（图6 ） 。高的电压保证高马力生产。此系统可以提供高扭矩，低电流（热）由于电机再生的缘故。高速无负载时也可以完成。这在很大程度上是不可能实现的在原来的面板上。 图5.节省能源降低序列 所不同的是发现时的IGBT是在其起飞周期（图7 ） 。在这种情况下，电机作为发电机，产生循环电流通过反激式二极管和维护自诱导电动机电流。这种效应降低了纹波，并规定这是目前所无法提供的原始动力源。减少电流负载馈线系统和硬件进一步增加了总储蓄封装。 下列项目是重要的考虑因素当确定是否该系统将与应用程序一起运作。 IGBT是最新的部分设计，使得面板在250伏特直流下工作。他们结合了双极型晶体管（高电压和电流）的优势，金属氧化物半导体场效应晶体管（ MOSFET ）的电源（低功耗和高开关） 。 IGBT是半导体，结合高电压和高电流双极型晶体管（双极晶体管）的低功耗和快速开关的MOSFET 。因此， IGBT提供更快的速度和更好的驱动器和输出特性比功率晶体管，并提供更高的电流能力比同等高功率晶体管。 图6.IGBT开启时提升了电流 散热，包括考虑空气温度和空气流通，是必不可少的正常运作的任何固态继电器。有必要提供一种有效的手段，消除热的IGBT 。必要时，使用适当的散热片也不过分，因为它直接影响最大可用负载电流和最高允许环境温度。高达百分之九十的问题晶体管是直接相关的热量。没有注意这个细节可能会导致不适当的开关（锁定） ，甚至完全破坏IGBT 。如果该设备以往的内部温度达到105摄氏度 ，这将是永久摧毁。一个韦尔北美公司遇到的问题，那是程序温度在降低由于过度的热量。当电流减少到不能控制驱动器，它将会停止对软件的限制。晶体管开发热而导致的正向压降通过路口的IGBT。除了这一点，将导致热量减少（软件削减）的负载电流可处理。如果需求过大，该计划旨在关闭。 图7.IGBT关闭时电机电流在继续提升 当安装固态继电器（序列）在一个封闭的地区时，应当十分小心。只要有可能，固态继电器应安装在单独的散热片上。序列不应该没有适当的操作或散热自由空气，因为它们将在这个负荷下自毁。一个简单的方法来监测温度就是将在热电偶下安装螺钉。如果基温度不超过45摄氏度，是操作系统的SSR在其最佳水平。请记住，移除SSR的热量和转让热空气中的电器附件。反过来，这必须空气流通和转让其热量到外面。喷口和强制通风良好这一途径来实现这个目标。 图8. IGBT和元件安装在散热片上 图9.在IGBT的外部安装风扇散热 半导体引信是唯一可靠的方式来保护序列。他们也被称为限流熔断器，提供极快的开放，同时限制让通过远低于目前的故障电流，可以摧毁半导体。这种类型的导火索往往是昂贵的，但比较便宜的损害可能发生，提供了一个手段，充分保护序列对高电流超载。一个保险丝评价是有用的帮助在适当的设计，SSR的能力是处理短路输出条件。设备，如断路器和熔断器缓慢打击不能作出迅速反应，足以保护SSR在短路条件和不推荐。每一个SSR有一个类别。这样做是为了选择一个引信匹配的能力，固态继电器的同一时间。 电机开关和动态载荷，如汽车和螺线管，可以建立特殊问题的序列。要注意高初始浪涌电流，因为它的启动阻抗通常很低。作为电机转动时，它开发了一个反电动势（ CEMF ）来抵制流动的电流。这CEMF也可以添加到线电压的应用，并创造过电压条件在关闭和再生次。应当指出的是，过电压引起的感应电压一倍或CEMF从电机不能得到有效处理，增加电压瞬态抑制器。抑制器，如金属氧化物变阻器（ MOVs ）通常是专为简短的高电压尖峰，并可能被摧毁的持续高能量传导。电压转储电阻可能需要在极端的情况下，应设计，以满足系统的需求。因此，重要的是序列中选出能承受的最高预期持续的电压。 图10.面板风扇散去内部热量积聚 图11.安森美半导体提供最好的熔断器保护固态继电器 遇到的问题，同时运行的200马力的双驱动器很少，但值得一提。该计划允许设置许多变量（即，速度，电流，制动初始电压） 。大多数这些不利于驱动器或电机如果设置不正确。虽然留在驱动器的规格是安全的，这可能不会产生预期的行动。环境温度也必须加以考虑，因为最有用的应用是近高温度区。以下是几个问题（和解决方案）观察在安装过程中和试验： (1)第一个问题出现当提出过度制动初始电流。接触了方向闪现和进站。此外，紧急制动接触出现高热量。减少制动初始电流和功率上的时间更短的时间解决了这个问题。 (2)霍尔效应晶体管和IGBT被认为是错误的部分和/或线路系统，但这无法复制的。许多人怀疑部分取代，但它的内部面板确定，环境温度是这个问题。这是解决散热风扇的入口和IGBT的散热片的方法。 (3)温度削减通常导致错误。结果发现，一个新的起重机操作员不喜欢经营提升全速。长远来说，时间和更高的IGBT周期中造成不必要的加热板。减少外地当前设置来缓解这一问题。这增加了降低速度，但大大降低了IGBT的电压下降，反过来又减少其散热。冷却风扇来消除这个问题。 (4)一切功能必须同线路分开，因为所有线路由一个共同的电容过滤系统提供。这意味着，典型的方式“拉电机断开和运行控制只有”排查不工作。该小组的诊断和故障排除提供的信息是非常有帮助的。 (5)缺乏电子知识的电工是一个关切的问题。当生产停工是至关重要的，解决的时间是一个高价位的商品。这最终对电工造成压力，造成挫折。该解决方案是确保工作人员是参与项目的设计和安装的工作中。培训是至关重要的。如果维修人员不是提高维修技术的速度，失败是有可能的。两个所有电气团队成员的培训班被成立了。 一年后，维修的实际材料和劳动力节省了计算，回收期为6.2个月。节约成本和提高效率大于预期。这导致了下一个驱动器转换，这是定于2006年。与合作努力的销售商，制造商，工程师和终端用户， 韦尔北美公司那大大改善其竞争能力为竞争成功。 致谢 作者要感谢前总务主管弗雷德施瓦兹和韦尔北美公司全体工作人员的努力。没有他们的帮助，该项目可能永远不会走到这么远的地步。 参考资料 1 克里奇，河， “节能---直流数字和直流接触器提升机控制系统， ”钢铁学院， 2005年5月， 225-228页。 2 http://ray.eeel.nist.gov/modval/database/contents/reports/igbt.html 3 http://web.ece.umr.edu/computing/unix/software/matlab/toolbox/powersys/igbt.html 4 http://www.fujisemiconductor.com/old_pdf/app_notes/r_ipm.pdf 5 http://www.mathworks.com/access/helpdesk_r13/help/toolbox/physmod/powersys/igbt.html