Slew-region instability of permanent-magnet stepmotors

In treating the phenomenon of the slew-region instability of the permanent magnet stepmotor the authors are aware of its strong relation to the problem of hunting in synchronous machines. The latter problem was treated by Rogowski and many others from 1915 onwards but the authors believe that their approach leads to a more detailed understanding of the phenomenon of spontaneous vibrations, as well as the fact that the results are obtained by way of simple and straightforward mathematics.