Evaluation of a linear hybrid microstep motor by means of magnetic flux measurements

There are two step motor principles for building up linear microactuators: variable reluctance (VR) and hybrid. While the VR motors use only soft magnetic material for guiding the magnetic flux, hybrid motors use permanent magnets as a source of static magnetic flux, as well. The benefit is a greater driving force, while the drawback is a more difficult fabrication process. The working principle of the hybrid motors requires the flux created by the permanent magnets to be of the same magnitude as the flux created by the excited coils. Therefore, it was investigated how to ensure that the two fluxes match. This paper describes the approach taken and the resulting advances in the fabrication of the micromotor.