Is saturation a blessing in disguise?

The patent by J. and J. Jarret caused quite a stir among engineers owing to the somewhat surprising claim that the performance of reluctance machines could be enhanced by the deliberate introduction of saturated zones, e.g. by way of reduction of iron at appropriate places in the magnetic circuit. Lawrenson et al. recently reported on experiments to examine this matter. It is, however, still not clear to what extent the Jarret claim holds, and, more specifically, which are the boundary conditions for such feature, if any. In the paper the authors will try to answer these questions and will introduce an approach to relevant torque calculations and its verification by experiment. Finally, feasibiliiy will be discussed.