同步电机转子的检修探讨

同步电动机转子时常由于磁极松动,导致电机振动现象严重.本文以烧结厂1#抽烟机转子检修为例对同步电机的转子检修进行探讨,很好的解决了这个问题.同时为同步电机转子检修提供了一整套检修方法.     

风电典型机型的闪变严重度分析

风力发电机组的并网运行对当地电网的电能质量有不良影响。为此．根据定速机型、变速机型引起电压波动和闪变的原理及并网风电机组电能质量的国际电工标准IEC61400—21，讨论了测量风电机组输出闪变的方法，给出了两种典型机型的短时闪变严重度与风速的关系实验曲线，并对不同风速段的闪变成因进行了分析。结果表明，变速风电机组在高风速区域综合应用桨叶节距角和变流器控制实现输出功率的稳定能够减小短时闪变严重度，在低风速区域追求最佳风能利用系数将使闪变严重度值增高。     

接地故障保护的设置和整定(三)

7 TT系统接地故障保护 TT系统的电源中性点直接接地,而电气设备的外露可导电部分则经各自的PE线接地。这样在大多数情况下,由于故障回路包括两个接地电阻,使接地故障电流太小,不足以使过电流保护动作切断接地故障电流。而且由于故障电流小,故障点未被熔焊,故障点阻抗是难以估计的接触电阻。因此,TT系统接地故障回路阻抗和故障电流难以估算。所以,必须设置漏电电流动作保护。     

Mg-doped LiNi0.5Mn1.5O4 spinel for cathode materials

Lithium-ion batteries are becoming more and more important not only for portable electronic devices, but also in prevision of high power electric vehicles. In such an optic, deep studies regarding all the components of a secondary battery are in development. In this study, high voltage cathode materials have been selected. Crystals with spinel structure have a 3D vacancy pathway suitable for Li-ions transport. The material under study was LiNi_0.5Mn_1.5O₄ doped with magnesium replacing the nickel. Various samples were synthesized via three different routes: a solid-state method, a modified sol–gel method and a xerogel method. The structure and morphology of the powders were analyzed with HRTEM and XRD. Electrochemical tests were also performed. A wide range of particle sizes (from micro to nanosize) was the result of the different synthesis routes. Unfortunately pure materials were not always obtained. The electrochemical tests showed improvement of the material's cyclability, by reducing the particle size. The electrochemical tests further confirmed the existence of a Li_1+dMn_2−dO₄ impurity. The results are quite promising, however, further improvement of the purity of the electrode composition are needed.     

计算机系统在钢卷库库区管理上的应用

主要介绍了钢卷库过程计算机系统(CYC)管理库区的方法,包括钢卷的堆放方式、库区管理的策略,以及平整生产等内容,并且简述了CYC系统的运行情况。     

Absolute Measurements of the Magnetic Field Generated by Different Coils in the Center of EGYPTOR Tokamak

The present work is devoted to measure the absolute magnetic field produced by different coils in the EGYPTOR tokamak using a calibrated pickup coil. Scaling these measurements in different equations connected with the discharge currents from each supply system are performed. The pickup coil used in the present study is well calibrated with Helmholz coils at the IPP in Prague, Czech Republic. A 0.2% deviation has been found between an evaluation done in the present study and the calibration using Helmholz coils. Experimental measurements of the toroidal magnetic field are in good agreement with calculations to within 2%. Very low values of stray magnetic field components arising from TF and OH coils are recorded which proves that the compensation coils for these components are sufficient.     

Scanning electron microscope electron detector with a radial type discrete dynode electron multiplier

A discrete dynode electron multiplier with radial flux of electrons was built and tested in the range of low‐voltage scanning electron microscopy as a backscattered electron detector of topographic contrast. The multiplier collects backscattered electron emitted in a specific range of take‐off angles and over the whole azimuth angular range enabling large solid collection angle. Multipliers with different dynode shapes were studied theoretically with the use of the software for particle optics and three assemblies were built and tested experimentally. The gain estimation, assessment of the type of detected electrons (secondary electron or backscattered electron), imaging the spatial collection efficiency and signal‐to‐noise measurements were performed.     

阳极炭块压降测试的方法与分析

本文通过阐述新的阳极炭块测试方法，提出了降低阳极炭块Fe-C压降的思路，并分析了降低阳极炭块压降对我公司经济效益的影响，可供同行参考。     

An investigation of the relation between the temperature dependences of the initial unbalance and the output signal of resistance strain sensor bridge circuits

The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage under external physical action. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007.     

智能型MNS低压开关柜

MNS智能低压开关柜是ABB公司的新一代产品。除具有设计灵活、结构紧凑和免维护等特点外，安全可靠性是其最突出的优点，包括抗故障电弧、可靠的绝缘分隔及接插性能、可靠的抽屉单元和温升限制。采用和智能化电动机控制中心INSUM及配电智能化控制和能量管理系统ESD2000的完美结合，开发了了基于现场总线的智能化的系统解决方案。