Radial force characteristics of multi-consequent-pole bearingless motor

Multi-consequent-pole bearingless motors can be used in low speed rotating and swinging stages (or platforms) under specific conditions. A test machine has been designed and built and in this machine two axes of freedom are actively controlled in the radial x-y directions. The suspension windings are of a novel toroidal shape, i.e., they are wound around the stator yoke. This produces a low axial length because the coil ends are compact. In the paper, a multi-consequent-pole rotor design is presented. The design procedure considered the leakage fluxes and magnetic saturation and used a three dimensional finite element analysis before the machine was constructed and tested. This paper proposes a novel structure for the suspension windings and the rotor. The suspension of the rotor was found to be successfully achieved and these characteristics are put forward in the paper.