Bucyrus Erie Company

James H Treiber

Donald M Mains

Edward H Christian

A Ward-Leonard drive system for a dragline excavator includes a feedback circuit which connects to the motor-generator armature loop to sense a signal proportional to motor armature counter emf and rate of change of armature current. The feedback circuit takes the second derivative of this signal and applies it to a circuit which controls motor speed and torque. The feedback circuit alters the response of the drive system to sudden increases in motor load caused by rough digging and thereby reduces transient loading on the mechanical elements of the drive system.

Growing community of inventors

Milwaukee, WI, United States of America

James H Treiber