Abstract: A brushless commutated torque motor suitable for use with a rotary low frequency sound reproducing apparatus, includes a shaft having a longitudinal axis, a position sensor, a rotor having a plurality of permanently magnetized rotor pole sectors, the rotor being mounted for rotation upon the shaft, and a stator having a plurality of stator poles and stator winding slots disposed alternately therein, the stator slots having stator windings therein driven by individual power amplifiers in response to a control signal, the stator having commutation between stator windings controlled by sensing of rotor angular position by the position sensor, with each rotor pole sector being configured and disposed such that a plurality of stator poles are axially adjacent to each rotor pole sector and each rotor pole sector is angularly separated from adjacent rotor pole sectors by a selective number of stator poles.

Abstract: Apparatus (21) is described for reproducing low frequency sound in response to an applied electrical signal having a rotary acoustic radiator (22) comprised of a chamber (26) having a rotor assembly (58) including a shaft (61) and movable vanes (71, 72) secured to the shaft rotatably mounted in chamber for rotation on a longitudinal axis. Stationary vanes (62, 63) are mounted in the chamber and extend generally radially between the chamber walls and the shaft. The chamber has ports (64, 66, 67, 68) therein opening into the chamber and disposed adjacent the stationary vanes on opposite sides of said stationary vanes. The movable vanes are disposed on opposite sides of the stationary vanes and extend generally radially between the chamber walls and the shaft.

Abstract: In a radial gap dynamoelectric machine a composite stator ferromagnetic structure having reduced losses is formed using thin section metallic glass or electrical steel strips folded or otherwise periodically deflected on one side or another of one or more planes perpendicular to the machine longitudinal axis edge wound to form a ring-like magnetic structure surrounding separate stator tooth assemblies formed of traditional or thin-section sheet or powdered ferromagnetic materials. Alternative structures are described.

Abstract: In a radial gap dynamoelectric machine a composite stator ferromagnet having reduced losses is formed using fanfolded thin section metallic glass or electrical steel strips edge wound to form a ring-like magnetic structure surrounding separate stator tooth assemblies formed of traditional or thin-section sheet or powdered ferromagnetic materials. Alternative structures are described.

Abstract: Energy efficiency of electric motors and transformer, inductor and ballast apparatus is increased through use of amorphous ferromagnetic materials and thin section electrical steels by methods using folding of lamination stock, forming of lamination stock after folding or punching, and stacking to form substantially solid flux-conducting structures. Such apparatus may employ multiple ferromagnetic materials to conduct major portions of the magnetic flux in the apparatus magnetic circuit. Apparatus is also described in which magnetic and mechanical support functions reside in differing ferromagnetic or structural plastic materials in composite structures.

Abstract: Apparatus for reproducing low frequency sound in response to an applied audio signal having a rotary acoustic radiator comprised of an enclosure having a cylindrical sidewall and end walls adjoining the sidewall and forming a cylindrical chamber. A rotor assembly including a hub and movable vanes secured to the hub is rotatably mounted in the chamber for rotation on a longitudinal axis. Stationary vanes are mounted in the chamber and extend between the cylindrical sidewall and the hub and extend between the end walls. The enclosure has ports therein opening into the chamber and disposed adjacent the stationary vanes on opposite sides of said stationary vanes. The movable vanes are disposed on opposite sides of the stationary vanes and extend between the cylindrical sidewall and the hub and between the end walls.