Reliance Electric Company

George Scott Dixon

Theodore A Oliver

James W Wilson

Lawrence F Flaczynski

Edward O Gilbert

A direct current motor control system for generating current command signals to a unidirectional armature controller and a bidirectional field controller. A motor speed command is compared with the actual motor speed to generate a speed error signal. The system generates a current command signal from the average of the speed error signal wherein the current command signal is proportional to the square root of the desired motor torque. The absolute value of the current command signal is the input to the armature controller and the field controller receives the current command signal wherein the polarity of the signal determines the direction of current flow in the field winding for controlling the direction of rotation of the motor.

D. C. motor control system

A tachometer for generating a digital output signal representing velocity which is a stepped approximation to a 1/t velocity versus time curve where t is the time required to travel a fixed distance. High resolution is obtained by dividing the 1/t curve into octaves and an approximate straight line portion. A nonlinear counter counts a predetermined number of pulses during each octave as the time of the counting interval for succeeding octaves is doubled. Therefore, the counter total and the number of octaves completed after time t represents velocity. After completing eight octaves, the nonlinear counter counts at a predetermined frequency to generate a straight line approximation of the 1/t curve as it approaches zero velocity. The digital output can be converted to analog form by a digital-to-analog converter and operational amplifiers having an amplification factor determined by the number of octaves completed.

Growing community of inventors

Ann Arbor, MI, United States of America

George Scott Dixon