Re-inventing the electrical machines curriculum

Undergraduate courses in electromechanical energy conversion are typically oriented toward the steady-state analysis of electrical machines. The advent of low-cost computer power and the availability of numerical software tools provide the opportunity to fundamentally reorient the pedagogical approach to the topic. A new approach is consistent with the developing need to emphasize the study of new machine designs and machines employed for control purposes as well as machines for use in more traditional power applications. This paper presents the results obtained from simulations developed as an integral part of an undergraduate electrical machines course at the University of Dayton, USA. Sample simulation files are presented to demonstrate the ease with which the matrix model of the machine is transferred to the program. The matrix models and simulation results of the following machines are included: the single-phase transformer; the variable-reluctance machine; the cylindrical-rotor dual-winding machine; the symmetrical two-phase induction motor; a PWM-controlled DC machine; and an inverter-driven brushless machine. The selected machines provide a systematic framework for analysis and simulation and present problems of increasing complexity to the student     

Study and improvement in the radio communication quality for rotating electrical machine

Electrical Engineering - The wireless communication for rotating electrical machines is beneficial for diagnosis purposes as well as real-time monitoring. The electromagnetic waves propagation...     

采用快速后减模控制系统的大拉机设计与研究

介绍了采用快速后减模控制系统的DL400系列铜铝大拉机的机械及电气控制原理和设计方案,重点论述了该快速后减模控制系统的设计特点及实现原理和DL400系列大拉机及其配套部分在设计时注意到的一些问题。     

冷轧硅钢取代热轧硅钢的电机设计特点

冷轧硅钢取代热轧硅钢是硅钢材料发展的必然趋势，不同牌号冷轧硅钢由于磁感，铁损的差异，对电机性能的影响不尽相同，文章分析了各种牌号冷轧硅钢的性能情况，以三种典型电机为例讨论了用冷轧硅钢取代热轧硅钢片时电机设计特点和牌号的选择。     

冻结磁导率先进技术及其在高性能电机研发中的应用

如何考虑磁场饱和的影响是当前电机设计中一个亟待解决的重要问题。近年来提出的冻结磁导率技术越来越多地被应用到电机负载电磁性能和参数计算中。本文详细阐述了冻结磁导率的原理及其在各种电机中的应用现状。研究表明,冻结磁导率技术可以用来精确分离各种电机负载状态下的电磁分量,如磁场、磁链、电感、转矩、转矩波动、反电势和端电压、弱磁性能以及径向力等均可以用冻结磁导率技术预测,并用来辅助电机及其驱动控制系统的设计。因此,冻结磁导率技术为高性能电机的研发提供了一个全新的方法。     

Sensitivity of Electrical Appliances to Harmonics and Fractional Harmonics of the Power SYSTEM's Voltage. Part I: Transformers and Induction Machines

The work described in Part I deals with analytical as well as experimental investigations of the effects of harmonics on singleand three-phase transformers including singleand three-phase induction machines as they occur in electrical appliances. The systematic treatment shows that single-phase and three-phase induction machines are more prone to temperature rises due to voltage harmonics than transformers. The work described has been supported by the U.S. Department of Energy.     

Life tests of electric insulating epoxyisocyanate impregnating compound

Electric insulating epoxyisocyanate impregnating compound (EPIC) is tested with respect to its electrical (specific spatial electrical resistance, tangent of dielectric losses, and electrical strength), mechanical (cementing ability) and chemical (mass losses) properties. It is shown that an epoxyisocyanate impregnating compound is a heat resistant compound of C-class and it can operate for a long time under 200°C and for a short time under 260°C.     

电机优化设计技术发展情况

在分析电机优化设计技术文献的基础上，总结了国内在电机传统优化设计方面的特点，几种主要的新型算法及其在电机设计中的应用，电磁场逆问题的优化设计，以及电机优化设计技术的发展动向；并对该领域未来的发展趋势作了展望。     

电机优化设计技术发展情况

在分析电机优化设计技术文献的基础上,总结了国内在电机传统优化设计方面的特点,几种主要的新型算法及其在电机设计中的应用,电磁场逆问题的优化设计,以及电机优化设计技术的发展动向;并对该领域未来的发展趋势作了展望。     

Main trends in the development of electric machines and the electromechanical systems on their basis

Modern trends in the development of electric machines and the electrical systems developed on their basis have been represented. It is shown how the worldwide processes (price increases for the generation of energy, depletion of the world’s reserve of liquid hydrocarbons, limitations caused by global worming) cause trends in the activities of scientists and electrical engineers, as well as electric machine engineering and power electronics as a whole.     

Simulation of fault-to-ground currents in the winding of an asynchronous motor stator in a network with insulated neutral

In this paper, results of comparison of the ground-short-circuit currents in electrical machines obtained using a new simplified calculation method and some circuit simulation systems, as well as by experiments, are reported.     

Space phasor theory and control of multiphase machines through their decoupling into equivalent three-phase machines

This paper first introduces the space phasor theory from a general mathematical viewpoint and, above all, from a physical one as well. The theory is then applied to the particular case of constant airgap multiphase machines (MMs) fed by arbitrary voltage waveforms. It is mathematically proven, and thereafter checked by simulations too, that these machines can be split into a set of equivalent three-phase machines mechanically coupled but electrically independent. This electrical decoupling leads immediately to develop the very fast torque control schemes of the MMs. All of them boil down to a mere extension of those already used in the homologous three-phase machines.     

小功率电机钢板接线盒的模具设计与制造

在分析小功率电机钢板接线盒结构的基础上,通过初步计算、生产试验、修正的反复进行,准确地确定了该类零件的坯料尺寸,设计了它的落料压型复合模,并介绍了该模具的制造要点.     

Ni-P合金化学复合镀技术及在电力系统中的应用前景

文章综述了近年来Ni-P合金化学复合镀技术的研究进展,主要包括耐蚀性化学复合镀和自润滑化学复合镀的制备、特性及应用,并介绍纳米颗粒化学复合镀的最新研究进展,指出纳米化学复合镀推广应用于电力有着十分广阔的前景.     

Vibratory behavior reduction of electrical machines through materials properties evaluation

Most of the electromagnetic devices, especially electrical machines, have the disadvantage to be exposed to high vibrations caused by magnetic forces. The aim of this study is to propose a methodology to optimize the cylindrical stators generally used in electrical machines regarding the vibration phenomena. Techniques for vibration reduction require knowledge of the proper frequencies, which depend on mechanical shapes and dimensions as well as material properties such as mass density, Young's modulus and Poisson's ratio. This paper proposes a new approach which is based on the identification of mass density (lamination stacking factor) and Young's modulus in the goal to minimize the vibratory behavior of electrical machines. In this goal, we have used artificial intelligent and finite element method (FEM) analysis to solve the magneto‐mechanical inverse problem (IP). In the proposed approach, a Multilayer Perceptron Neural Network (MLPNN) is used as a forward model in order to decrease the FEM time consuming. Thus, a Genetic Algorithm (GA) is used to solve the IP in a reasonable time of running. An example study of an induction machine proves that the developed approach may be applied in both design and identification applications. Copyright © 2011 John Wiley & Sons, Ltd.     

现代汽车电机的发展状况

根据现代汽车电机的广泛应用，详细地介绍了汽车交流发电机、起动机、空调电机和门窗升降器电动机的功能和结构，并指出其未来的发展趋势。     

Partial discharges. Their mechanism, detection and measurement

Different partial discharge (PD) detection and measurement procedures suitable for use on cables, capacitors, transformers and rotating machines are examined and compared. Both narrow and wide bandwidth PD detectors are considered; particular attention is given in regard to their suitability to different types of electrical apparatus and cable specimens under test as well as their applicability to discharge site location and their capability to detect different forms of PD. A rather substantial portion of the discussion is devoted to the use of intelligent machines as applied to PD pattern recognition in terms of either PD pulse-height/discharge epoch (phase) distributions or discharge pulse shape attributes.     

A UNIFIED THEORY OF TORSIONAL OSCILLATIONS IN ELECTRICAL MACHINES AND ELECTROMECHANICAL SYSTEMS

ABSTRACT

The torsional oscillations in electrical machines are not only dependent on the machine quantities, but also on the peculiarities of the shaft-line and network. Free (SSR or hunting) as well as forced oscillations of synchronous or asynchronous machines can be treated by a unified theory taking proper account of the aforementioned influences. This will be illustrated with the help of practical examples and the basic guidelines of the theory will be outlined in short.     

Compounding of ethylene-propylene polymers for electricalapplications

Compounding is the technology of converting the raw rubber resin into useful materials through the addition of various ingredients. The resulting composition is called a compound. A typical compound usually has the following ingredients: ethylene-propylene rubber, filler/reinforcing agent(s), plasticizer, antioxidants/ stabilizers, flame retardants, process aids, ion scavenger coupling agent, curing coagent, and curative. Proper selection of the ingredient(s) in each category requires that consideration be given to the desired physical, electrical and environmental properties, as well as cost, ease of mixing, chemical stability and ease of processing. Frequently these considerations may require compromises in one characteristic in order to improve another. In the following discussion, factors to be considered in the proper choice of each ingredient for the compounding of ethylene-propylene polymers are explored     

基于Web的网络化电机计算机辅助设计系统

计算机辅助设计技术网络化能有效地整合各种科技资源，提升创新能力。该文提出了一种基于Web的网络化电机CAD系统架构和技术路线。阐述了网络化电机CAD系统的组成要素，信息流和数据流的传输特点。利用ActiveX组件技术和ASP(active server pages) Web应用程序开发技术，将电机CAD、ANSYS有限元分析和HTML有机结合。详细给出了电机设计ActiveX DLL的具体实现，建立了直接用网页浏览器进行电机设计仿真的集成平台，并给出具体示例，验证了系统架构的可行性和有效性。