NUMERICAL ANALYSIS AND EXPERI- MENT OF UNSTEADY THERMAL FIELD OF ROTOR PLATE FOR EDDY CURRENT RETARDER

The physical model based on heat transfer theory and virtual boundary method for analyzing unsteady thermal field of rotor plate for eddy current retarder used in automobile is established and boundary conditions are also defined. The finite element governing equation is derived by Galerkin method. The time differential item is discrete based on Galerkin format that is stable at any condition. And a new style of varying time step method is used in iteration process. The thermal field on the rotor plate at the radial and axle directions is analyzed and varying temperature at appointed points on two side-surfaces is measured. The testing and analytical data are uniform approximately. Finite element method can be used for estimating thermal field of the rotor plate at initial design stage of eddy current retarder.     

三维有限元法分析频率对接地电阻的影响

提出了用涡流场的A-V有限元分析方法计算接地系统接地电阻的方法,分析了入地电流频率的变化对接地电阻的影响。计算结果表明,频率对接地体自身电阻的影响较大,但对散流电阻的影响很小。     

三相异步电动机运行指标的分析

利用电机学理论分析了影响电机起动转矩、起动电流、最大转矩和最小转矩的因素。     

Influence of additives on electrodeposition of bright Zn-Ni alloy on mild steel from acid sulphate bath

The influence of a condensation product (CP) of veratraldehyde (VRTD) and p-amino benzoic acid (PABA) on Zn-Ni alloy electrodeposited onto mild steel was studied in acidic sulphate solutions. Ethylenediaminetetraaceticacid (EDTA) and cetyltrimethylammoniumbromide (CTAB) were used as complexing and wetting agents, respectively. The effect of bath constituents, pH, current density and temperature on nature of deposit were studied through Hull cell experiments. The bath constituents and operating parameters were optimized. Deposit properties and corrosion resistance were discussed. Throwing power, current efficiency and polarization studies were carried out. SEM photomicrographs of the deposit obtained from optimum bath revealed fine-grained deposit of the alloy in the presence of condensation product and hence modified the morphology of zinc-nickel alloy deposit. IR spectrum of the scrapped deposit showed inclusion of addition agent.     

高速电路中地电流的影响及其对策

从理论上分析了产生地电流干扰的原因，从而在实践上提出了一些经常被忽略，却是行之有效的方法来减小地电流的干扰，设计出高质量的电路。     

主电机轴瓦异常情况分析解决办法

介绍南钢中板厂四辊轧机主电机轴瓦一种非典型故障现象，原因分析及解决办法，提出了对类似问题个人见解。     

万用表电压测量法查找直流接地故障

直流电源是发电站的主要设备，一旦直流系统发生接地故障，将会严重地危及到发电站的安全和经济运行。因此，本文介绍一种简单易行，能快速找出直流接地点的方法一万用表电压测量法。     

无磷洗涤剂的现状及存在问题

含磷洗涤剂中含的“磷”主要是STPP，作用很大但对环境的危害也很大，它是造成地表水体出现富营养化的重要原因之一，所以许多地方政府都在实行“禁磷”——禁止销售、使用含磷洗涤剂。现在我国使用的无磷洗涤剂中代磷助剂主要有3种，其中4A沸石用量最大，但它会对环境带来新的问题。主要介绍了含磷洗涤剂的危害及无磷洗涤剂的应用现状，指出了我国禁磷后将面临的问题。     

光电双基区晶体管(PDUBAT)的器件模型

本文在考虑了晶体管的小注入效应和大注入效应以及基区宽变效应等因素后,首次用近似和简化的数学表示式和相应的等效电路,描述了光电双基区晶体管(PDUBAT)负阻形成的机理并使负阻区和谷值区的理论计算和实验结果一致性很好.     

酸性盐水及其配套装置的应用与运行

介绍了对进槽盐水由酸碱性改为微酸性的技术改造，减少了副反应的发生，从而提高了电解槽的电流效率。