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:
May. 12, 1987
Filed:
Oct. 31, 1985
Robert E Hager, Penn Hills, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
In a protection system for a complex process control system which generates three independent actuation signals, the power interface circuit includes three pairs of switches arranged in three parallel groups of switches connected in series with the load and a voltage source. Each group of switches includes two switches selected from different pairs of switches and connected in series. Normally closed switches are used with normally energized loads and normally open switches with normally de-energized loads. Logic gates control actuation of each individual switch in response either to an associated actuation signal or a test signal generated by a microprocessor. The microprocessor generates a sequence of patterns of test signals which result in various combinations of switch actuations. The current through each group of switches resulting from each combination of switch actuations is compared by the microprocessor with expected values to evaluate circuit performance.