Permanent magnet motor

TLDR: In this paper, the stator members are formed of mild low-carbon steel that is annealed after fabrication, and the rotor is a permanent magnet ring with as many poles as the stators, mounted in a single unitary bearing structure.

Abstract: A small permanent magnet synchronous motor having one or more pairs of stator sections mounted in tandem. Each stator section includes a first annular stator member of generally U-shaped cross section with multiple pole pieces around the inside of the annulus parallel to the axis, the pole pieces preferably being of tapered construction. A similar second annular stator member interfits with the first stator member; the pole pieces of the second stator member are interleaved one-for-one with the pole pieces of the first stator member. The stator members are formed of mild low-carbon steel that is annealed after fabrication. In each stator section, a coil encompasses the pole pieces of the stator members. The rotor is a permanent magnet ring with as many poles as the stator sections, mounted in a single-unitary bearing structure. The motor is assembled by coating one inner frame member with an epoxy resin adhesive, assembling the inner frame members back-to-back on a gauge hub with interengaging index elements assuring accurate alignment at a displacement of 90* electrically between the stator sections, then adding the coils and outer stator members.