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王军伟 《机械工程与自动化》2011,(2)
将可编程控制器(PLC)应用到桥式起重机的变频调速中,实现了起重机电机的变频调速,并基于PLC的软件编程实现了通讯、PID控制等功能。此系统可实时监控起重机的现场运行状况和查询运行数据,可以通过控制室的人机交互界面启停电机、设定变频器的运行频率等,改善了传统桥式起重机的调速系统,提高了其可靠性和可操作性。 相似文献
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起重机调速绝大多数需在运行过程中进行,而且变换次数多,需采用电气调速。传统调速方案一般采用多速电动机、转子串多级电阻、定子调压、直流调压调速和调磁调速等方式。随着新技术和控制系统设备的发展,对就位精度要求高的起重机,交流变频调速技术在起重机领域得到广泛应用,为可靠调速及节能提供了全新的方案。本文研究变频调速技术和PLC在起重机中的应用,为起重机电控系统设计及改造提供参考。 相似文献
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桥式起重机变频调速及PLC控制的设计 总被引:5,自引:0,他引:5
介绍了VVVF变频调速和PLC控制技术在桥式起重机电气控制系统中的应用。对各驱动电机采用了步进式调速的控制设计,使起重机运行更平稳安全。同时,对PLC控制程序的保护、报警、故障处理等功能进行了阐述。 相似文献
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介绍交流变频调速技术在起重机中的应用及特点,阐述控制方式及起升电机的选取要点,并分析变频调速对起重机的特性、结构件及回转和行走机构的影响。 相似文献
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针对传统转子串电阻起重机调速性能较差,运行故障率高,维修复杂等特点,将可编程控制器(PLC)和变频器应用到港口门座起重机,重点介绍了控制系统的组成,硬件设计,软件设计和系统调试。最总实现港口门座起重机的变频调速性能,再通过PROFIBUS总线实现人机界面和PLC连接,可以实时监控起重机的运行故障和运行状态。实践表明,该系统可以广泛应用到门座起重机上。 相似文献
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变频调速技术。此种技术的应用有效的增强了设备的性能指标,在起重机调速系统中应用此种技术可以提高工作效率,提升工作的稳定性,可以在实践中充分的改善工作性能指标,具有较为显著的优势,变频调速技术可以完善起重机的操作系统,提升其安全性,在实践中应用广泛。对此,文章主要对起重机调速系统中的变频调速技术进行了简单的分析与研究。 相似文献
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为了解决绕线式电动机(转子串电阻)起动时对起重机的冲击问题,我们在制造QM63/1642型门式起重机时,针对起重机的运行控制电路进行技术改造,采用了先进的晶闸管串级调速技术,放弃了转子串电阻的调速方式,以寻求效率高、性能更好的调速系统。该起重机主钩起重量63t、副钩16t,主钩起升高度16m、副钩15-4m,起重机跨度42m。虽然在大车运行电路中采用了串级调速系统,但在操作上仍保持了与联动台主令操制器操作形式的一致。1 串级调速系统图1为晶闸管串级调速系统框图,该系统由主回路、给定及触发电路和… 相似文献
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太重为武钢二炼钢新炼钢厂承制的5台350/80 t铸造起重机,其主起升机构采用了定子调压调速控制系统。该控制系统中动力回路电源采用AC380V、控制回路电源采用AC220V;调速装置选用西门子SIMOTRAS HD 6SG70系列产品,3套装置并联运行,每套装置容量为900 A,此装置与起重机PLC系统以开关量方式连接控制;选用了2台国产YZR系列500 kW绕线电机,并联运行;系统动力回路基本原理如图1所示。 相似文献
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设计了磨粉机快辊轴承座的加工工艺和具体的工装夹具.利用卧式加工中心加工磨粉机快辊轴承座,辅以能够高效快速夹紧的夹具,既可以保证加工精度,又能够提高加工效率. 相似文献
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In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape. 相似文献
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本文以某些积算和双笔记录仪产品为例说明由于仪表功能设计的不合理或选型不当,影响了仪表的正常使用,制造厂和用户应关注这类问题。 相似文献
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通过分析膨胀套在实际使用产生滑移受阻现象、卡死现象原因的实质,并在分析产生问题原因的基础上提出了改进措施即:增加导向机构。 相似文献
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Polyvinyl pyrrolidone-Iodine complex (PVP-I) molecules were impregnated into the anodic oxide of an aluminum disk specimen. It was rubbed against a silicon nitride ball specimen using a ball-on-disk type friction test rig. Over the limited range of parameters studied (load: 0.2-1.0 N, sliding velocity: 0.6 mm/s, and sliding distance: 1-7 m), the coefficient of friction decreased to a value as low as 0.01 from values of 0.3 to 0.7 for the anodic oxide surface. Single-crystal iodine rubbed against silicon nitride showed a coefficient of friction of 0.1. The low coefficient of friction is attributed to the thin PVP-I film on the relatively hard anodic oxide. The mechanism of coefficient of friction reduction is the same as that of a thin soft film on a hard substrate. 相似文献
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针对目前市场对工业设计人才的需求,本文论述了我校在工业设计教育方面的改革措施,着重介绍了我校工业设计教育在软件和硬件方面所进行的一系列的改革。 相似文献
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The article provides a solution to the problem of contraction process modeling when measuring the flow of fluids and gases using differential pressure flowmeters. The article shows the feasibility of obtaining the coefficient of contraction from the mathematical model of the reduced/contracted flow of fluids or gases. An analytical expression is obtained for the coefficient of contraction, which agrees well with the results of the experiment. Analysis of this expression is performed and dependencies on the geometrical parameters of the pipeline and orifice plate are obtained. 相似文献