Gm Global Technolgoy Operations, Inc.

Donald F Harker, Iv

Jack W Savage

John S Maceross

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.

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Dayton, OH, United States of America

Donald F Harker, Iv