John J. Breen


The design of electromagnets is an iterative process in which the designer arrives at a solution to his design problem through repeated design trials. This procedure can be time consuming, and the resultant configuration may or may not be the best one for the constraints imposed on it. In addition, the designer must have a reasonable knowledge of magnetics to carry out these design steps. This paper presents the basic equations necessary for designing and analyzing a horseshoe-shaped D.C. electromagnet. With this base, two methods are developed to optimize a design for maximum holding force, subject to prespecified constraints. The first method is a graphical approach. The advantage of this method is that it presents, in a simple manner, the effects of changes in the design constraints on the final solution. The disadvantage is that the user must thoroughly understand the design equations to use it. The second method is part of a complete computer program package, written in Basic for an Apple 11+ computer. This package can be used by a designer with little or no knowledge of magnetics, the equation system, or the program. It not only designs the maximum holding force electromagnet for the constraints imposed, but also analyzes existing designs for many of the characteristics and sensitivities needed to insure a good production coil. The graphics capabilities of the Apple microcomputer are used extensively for maximum clarity. Holding force experiments are also presented, which are used to confirm the predicted results from the computer simulations. Good correlation is demonstrated for the configuration tested. Partial data is also presented for determining the B-H curves of various densities of sintered 50/50 nickel iron material. The combination of the program and paper is a useful tool for an engineer faced with an electromagnet design problem. It should result in a significant reduction in the time required to arrive at an acceptable solution.

Library of Congress Subject Headings

Electromagnets--Design; Electromagnets--Computer programs

Publication Date


Document Type


Department, Program, or Center

Mechanical Engineering (KGCOE)


Johnson, Ray

Advisor/Committee Member

Marletcar, P.


Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: QC760.B7 1984


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