Gm Global Technolgoy Operations, Inc.

John S Maceross

Jack W Savage

Jeff Allan Foust

Keith Richard Cook

Dennis P Thornton

Donald F Harker, Iv

An electric motor-driven brake pressure modulator having two auxiliary field windings, one which is connected in series with the rotor of a permanent magnet field DC motor and another connected in parallel with the series-connected winding and rotor, to produce different speed/torque performance characteristics depending on the direction of motor rotation. In forward motor rotation when the brake pressure is to be increased, the mmfs of the auxiliary field windings aid the mmf of the field magnets to produce a higher flux in the working air gap of the motor. This maximizes the torque characteristic of the motor for the development of adequate brake pressure. In the reverse direction of motor rotation when the brake pressure is to be decreased, the mmfs of the auxiliary field windings oppose the mmf of the field magnets to produce a lower flux in the working air gap of the motor. This maximizes the speed characteristic of the motor to quickly reduce the brake pressure.

Anti-lock brake system permanent magnet motor having differential

Motor control apparatus is disclosed for a motor driven vehicle power window mechanism including a flexible drive element, such as a drive tape, adapted to drive the window in a predetermined direction by being placed in tension by the motor. The tension of the flexible drive element is relieved by automatically reversing motor direction for a short time when the window reaches the desired position. The reverse motor rotation is accurately controlled to an amount sufficient to relieve drive tension but insufficient to produce unwanted reverse movement of the window by detecting the pulses of the armature ripple current as the successive commutator bars pass the brushes during reverse motor rotation, integrating these pulses and stopping the reverse motor operation when the integrated value reaches a predetermined reference.

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Spring Valley, OH, United States of America

John S Maceross