Optimum design of permanent magnets

THE ANALYTICAL APPROACH to the optimum design of permanent magnets which are subjected to demagnetizing effects is complicated by the fact that the slope of the minor hysteresis loops is not constant throughout the range of the main demagnetization curve. For some permanent-magnet materials, therefore, the slope variations are small, and a constant slope may be assumed without causing objectionable error to the design. For other materials however, as for instance the presently most widely used alloys of Alnico V and Alnico VI, the slope may vary considerably and hence will not justify such an assumption.