Composite magnetic structure for planar motors

Use of a single material for the magnetic flux path of an electromagnetic device requires a compromise of material properties. One such compromise, in a step-motor actuator design, is between high speed operation and high motor force. This corresponds to the use of a material that has low eddy current losses (e.g., ferrite) or high saturation flux density (e.g., Vanadium Permendur). No currently known material has both. When laminations cannot he used, as in the case of the platen for a two-dimensional linear Sawyer motor, the problem is most formidable. To overcome the problem a composite magnetic structure of multiple materials is proposed. Composites have advantages for actuators, sensors and other electromagnetic devices. Composite construction can simplify and lower cost of manufacturing.