The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1977
Filed:
May. 20, 1976
Applicant:
Inventors:
Edward H Christian, Brookfield, WI (US);
Donald M Mains, Greendale, WI (US);
James H Treiber, Milwaukee, WI (US);
Assignee:
Bucyrus-Erie Company, South Milwaukee, WI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318432 ; 318433 ; 318140 ; 318141 ;
Abstract
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.