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:
Nov. 18, 1997
Filed:
Jan. 03, 1996
James P Miller, Waukesha, WI (US);
Douglas P Cleereman, Greendale, WI (US);
Allen-Bradley Company, Inc., Milwaukee, WI (US);
Abstract
Improved redundant relay control circuits are set forth which prevent a load from being energized when any relay coil or contact or stop or start switch contact fails. A first circuit embodiment sets forth a plurality of branches with a cross-monitoring interconnection between a start branch and one of the two other circuit branches. The interconnection prevents a load from being energized when a start switch welds. Second and third circuit embodiments are configured such that the redundant control relay circuit remains inoperative until a fault is cleared although the main power across the circuit is temporarily removed. A fourth circuit embodiment operates independent of relay contact timing.