直流恒力电磁铁特性

电磁铁成本低、结构简单、结实坚固,在某些应用场合,为了改善其控制特性,希望采用恒力(或准恒力)特性的电磁铁.为了设计制作这种电磁铁,须解决两个基本问题:采用什么结构方案;主要尺寸应满足什么条件.针对上述两个问题,提出两种圆柱形直流电磁铁结构一盆形极面和锥形极面结构,在简化的等值磁路方法和分析磁路总磁导的基础上,导出产生恒力特性时电磁铁各主要尺寸之间的解析关系,分析各主要参数对力特性的综合影响.解析分析的结论可为进一步电磁场数值方法精确计算和试验研究提供初步的优选设计方案.解析计算结果与采用ANSOFT有限元电磁场软件计算的结果进行对比,证实所提出的方法和结论是正确的,对于恒力特性直流电磁铁的研发和设计是一种简便、适用的方法.

Direct Current Electromagnets with Constant Traction Characteristic

Electromagnets have the advantages of low cost, simple construction and ruggedness. In some applications, an electromagnet with the constant (or quasi-constant) traction characteristic is desirable for getting good controllability. In order to design a derect current electromagnet with constant traction characteristic, two basic questions including what kinds of magnetic circuit configuration are adoptable and what conditions should be satisfied must be considered. Focusing on solving the two problems, two kinds of cylindrical electromagnets are proposed and the corresponding conditions in the analytical function expressed by the related geometric dimensions of the electromagnet are also derived, based on the simplified equivalent magnetic circuit method as well as the analysis of the total permeance. Besides, the effects of the main parameters on the traction are discussed. The conclusions obtained by the analytical formulas may be used to provide a primary design, which then may be further improved by electromagnetic field numerical methods and/or by experiments. The comparison between the results calculated by the analytical formulas and by ANSOFT software is fairly good and it validates that the proposed method and the conclusions are simply suitable for the developing and designing of direct current electromagnets with constant traction.