用直流调速技术改造Y7520K万能螺纹磨床

本文介绍了可控硅直流调速系统的原理,用该技术改造螺纹磨床及其经济效益。     

电磁调速电动机控制系统的故障检修

以JDIA型电磁调速电动机的控制器为例，介绍电磁调速电动机控制系统的若干故障现象、原因分析及检修方法。     

粗加车床直流发电机组调速系统的改造

介绍原粗加车床直流发电机调速存在的问题,采用晶闸管—电机调速系统的改造方案、系统工作原理及参数设置等。     

全数字直流调速装置在曲轴车床上的应用

一、概述 C8120型卧式曲轴主轴颈车床,是内燃机车生产行业中,曲轴加工所普遍采用的大型机床。机床要求有较好的刚性和精度;主轴回转部分驱动,要有较高的启动转矩和制动转矩,过渡过程要短。其调速系统能对主轴直流电动机进行无级调速,适应频繁启动、停车及正反向转换运行。 C8120型卧式曲轴主轴颈车床,是武汉重型机床厂20世纪80年代的产品。该机床的主轴电机直流调速装置采用的是SI-MOREG-V57型直流调速系统。该系统自20世纪80年代安装     

祖克RS212浆纱机直流调速系统改造

1现状 我公司祖克尔浆纱机原来由直流调速系统进行调速控制。进口直流电机价格高，约1．58万元；故障率高，维修困难，严重影响生产的正常运行。     

西门子6RA70直流调速装置F30故障原因和处理

从软、硬件,系统优化等方面,分析西门子6RA70直流调速装置F30故障原因,给出故障处理方法.     

DCS800直流调速系统在高炉探尺控制中的运用

简介高炉探尺系统的组成、控制原理;ABBDCS800直流调速系统的控制原理及参数设定。     

模糊控制在镗床电机调速系统中的应用

介绍了模糊控制在镗床电机调速系统中的实际应用，以及控制效果。     

矿井提升机变频调速控制系统的研究与设计

矿井提升机负责井下的运送工作,如果出现故障将对矿井的安全生产造成非常严重的影响。本文首先对煤矿提升机进行了阐述,在此基础上对提升机直流调速性能及变频控制系统的设计进行了探讨,具有较高的实用价值。     

卷绕机调速系统变频改造

针对卷绕机调速系统存在问题,用交流变频调速进行改造。从负载特点、电机和变频器选型等方面阐述改造过程。     

利用闪存芯片作存储器的单片机应用系统

在测量及测试应用系统中,为使现场采集的数据在突发性的掉电过程中不被丢失,且能长时间的保持,可采用32M位闪存芯片KM29N32000TS作为存储器。本文以AT89S51单片机为例介绍它在单片机系统中的硬件连接和软件编程方法。     

双闭环调速系统的超调抑制

本文探讨了典型双闭环调速系统的超调，提出了系统超调的抑制方法。     

C2空间中广义解析函数的一个带位移的边值问题

阐述了一个以AT89C52单片机为核心的智能数字扭矩仪的硬件电路结构及软件设计。该仪器能对被测扭轴的扭矩值进行测量、存储和显示,并可判断扭矩正反方向,能够自动报警。     

Validation of Expert Systems for Innovation Management: Issues, Methodology, and Empirical Assessment

Faced with the complexities of managing new product development, most of us would welcome the support of a computer-based system that captures the knowledge and the reasoning capabilities of experts in our field. Considerable effort has been focused on the design and development of expert systems for applications such as new product management. However, design and development are only two steps on the path to successful implementation of a useful expert system. A rigorous validation process is essential for ensuring that the expert system performs as intended. Using the INNOVATOR expert system as an example, Sundaresan Ram and Sudha Ram propose and test a framework for validating expert systems designed for new product management. The proposed validation framework considers three aspects of the expert system: its knowledge acquisition methodology, its performance, and its utility. Validation of an expert system's knowledge acquisition methodology involves assessment of the knowledge sources used, the criteria for selecting human experts, and the methods used for knowledge acquisition. Using multiple sources improves the likelihood that the expert system will capture the necessary core knowledge. Similarly, selection of the experts who are to supply the knowledge used by the expert system should be based on reliable measures of new product expertise rather than ad hoc measures. The system's performance is evaluated through formal tests of the accuracy and the completeness of the knowledge base, the consistency and the accuracy of the decisions made by the system, and the reasoning process by which the system reaches its decisions. Such tests may involve direct examination of the system by experts, and Turing tests, which compare both the recommendations and the reasoning process of the system with those of selected experts. Both types of tests may involve experts from whom knowledge was acquired during the development of the system as well as experts who were not involved in the design and development of the system. Assessment of an expert system's utility focuses on user perceptions of system performance and utility as well as the design of the user interface. First, end-users must evaluate the relevance of the chosen problem domain. In other words, the validation process must verify that the expert system addresses an important problem that requires decision support tools. Second, the expert system must provide a logical, systematic approach to solving the problem. Finally, the expert system must provide a consistent, intuitive user interface.     

An experimental test of automatic mitigation of wholesale electricity prices

In several major deregulated electricity generation markets, the market operator uses an “automatic mitigation procedure” (AMP) to attempt to suppress the exercise of market power. A leading type of AMP compares the offer price from each generation unit with a recent historical average of accepted offer prices from that same unit during periods when there was no transmission-system congestion to impede competition. If one or more units' offer prices exceed the recent historical average by more than a specified margin, and if these offer prices raise the market-clearing price by more than a specified margin, the market operator replaces the offending offer prices with lower ones. In an experiment, we test an AMP of this type. We find that it keeps market prices close to marginal cost if generation owners have low market power in uncongested periods. However, with high market power in uncongested periods, a condition that may apply in many parts of the world, the generation owners are able to gradually raise the market price well above short-run marginal cost in spite of the AMP. We also test the effect of the AMP on the frequency with which high-variable-cost units are used, inefficiently, in place of low-variable-cost units.     

PLC在污水处理控制系统中的应用

本文介绍SBR法污水处理的PLC控制系统,该系统可广泛应用于污水处理厂及有关企业,实现污水处理的自动化,具有良好的经济和社会效果。     

计算机在控制理论频率法中的应用

介绍了利用计算机在输入系统参数后,能迅速显示和打印出开环幅相频率特性曲线,同时计算相位裕量和增益裕量及判定闭环控制系统稳定性的方法。此课题的研究促进了反馈控制理论中频率法的应用。     

数控技术的现状和发展

随着技术和经济的发展,数控机床得到了快速发展和应用。本文简述了数控技术的发展历程及在工厂中的应用模式。     

工业生产的自动监控系统设计

为了掌握化工等环境苛刻的系统的运行情况并且加以控制,自动监控系统是必须的。该文在硬件方面,以PIC18F458单片机为核心的嵌入式系统为例给出了一般的硬件构架。该结构在充分利用片上资源的基础上,充分考虑了系统的扩展以及远程监控;在软件方面,为了满足测量要求,提高测量精度,采用了软测量的方法。文中介绍了软测量的建模方法,并以神经网络为例给出了数据建模方法。     

探析我国当前通货膨胀的成因与治理对策

从2010年7月开始到2011年6月,我国衡量物价水平的两大指标CPI、PPI持续上涨,通货膨胀日益加剧,如何治理通货膨胀成为我国经济发展的重中之重.本文总结归纳了我国本轮通货膨胀的特点,以及引发我国通货膨胀的国际和国内因素,并在此基础上有针对性地提出了相应的综合性治理措施.