This paper presents a novel magnetless double-rotor flux switching motor for low cost cooling fan application. By creatively incorporating concentrated toroidal windings into a double-rotor middle-stator structure, the proposed motor not only realizes the flux switching feature, but also shortens the end-windings to improve its operational efficiency. To achieve a better performance, the motor dimensions, especially the stator and rotor pole arcs, are optimized. Meanwhile, with the introduction of a stepped air-gap, the torque at any rotor position is boosted and problems with zero output torque at starting is successfully avoided. The final optimized motor is analyzed using finite element method, and its validity is confirmed by the simulation results. ; Department of Electrical Engineering