Novel Design for Electromagnet with Wide Excitation Range

A novel design for an electromagnet with a wide excitation range is described. The magnetic field distribution of an electromagnet usually deforms as the excitation approaches the saturation level. This effect can be minimized if the saturation of the ferromagnetic material is uniform; the integrated magnetic field along a flux line \intH ·d s in the pole is uniform for all flux lines crossing the gap area of interest. This condition can be realized by adding vacant portions into low flux density regions in iron poles, and thus the magnetic flux density in the iron region becomes uniform. This magnetic flux density equalizer can be applied to a variety of magnets: flat dipoles, n-indexed dipoles, quadrupoles and higher-order multipole magnets.