CONTACTLESS DIRECT-CURRENT MOTOR Russian patent published in 1995 - IPC

FIELD: electromechanical engineering. SUBSTANCE: magnetic system of motor is fixed on rotor shaft and has nonmagnetic frame accommodating magnetic circuit components and auxiliary magnet arranged so that homogeneous-field space is formed. Rotor position detector built around Hall-effect transducers is installed in central part of space and held motionless in respect to rotor. While rotor is running, purely sine-wave signals are picked off Hall transducers, amplified, and applied to stator windings. Currents flowing through windings interact with rotor magnetic field and produce uniform electromagnetic torque. Because of relative immobility of magnetic circuit and auxiliary magnet, losses associated with reversal of polarity and eddy currents do not occur in the former. This enables manufacture of magnetic circuit from common-grade steel and making it nonlaminated thereby reducing manufacturing and material cost. EFFECT: reduced loss in magnetic circuit, facilitated manufacture, reduced cost. 2 dwg