DIRECT-CURRENT DRIVE Russian patent published in 2002 - IPC

FIELD: electrical engineering; high-speed induction motor drives. SUBSTANCE: ac drive has three-phase induction motor whose rotor speed is up to 12 000 rpm; its stator slots accommodate three groups of half-windings similar in design; half- windings related to same group are disposed in same slots and connected through transistor switches as follows: one pair of half-windings connected in parallel opposition is fed with phase voltage of power supply; other pair of half-windings connected in parallel opposition whose turn number is times greater than that of first pair is fed with line voltage of power supply which is shifted in phase relative to phase voltage through 90 electrical degrees. Proposed electric drive is distinguished by using four half-windings per pole per phase of stator which are connected through transistor switches to power supply. EFFECT: enhanced motor speed and power factor of drive due to using start and finish of supply voltage sine wave. 3 dwg