5 - Magnetic field analysis
Published online by Cambridge University Press: 05 August 2012
Summary
Introduction
Using simplifications for the actual paths followed by flux in a magnetic device provides an approximate model as described in Chapter 4, which is useful both for preliminary selection of component materials and dimensions and for performing sensitivity analyses. Before building a prototype device, however, it is often desirable to perform a more detailed analysis of the flux distribution, to investigate the validity of the prior assumptions, and perhaps also to account for effects such as saturation and eddy currents. Depending upon the complexity of the design and the nature of the effects to be studied, a more accurate analytical solution of the field distribution may be attempted directly, or with the aid of commercially available computer software. The objective in this chapter is to provide the basis for the representation of magnetic fields in complex geometries, and an understanding of the most common techniques that are presently available.
The nature of the fields that occur in electromechanical devices may be categorized into three levels of complexity. The most straightforward are magnetostatic fields, which result from excitation at zero frequency. Nevertheless, materials may still be represented by non-linear characteristics in magneto static field solutions, as in the case of saturation. The next level of complexity involves alternating current excitation, which adds the effects of eddy currents to the field solution.
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- Permanent Magnet Materials and their Application , pp. 113 - 133Publisher: Cambridge University PressPrint publication year: 1994