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:
Sep. 28, 1999
Filed:
Mar. 16, 1998
Richard Arthur Johnson, Aliquippa, PA (US);
Deborah Kaltwasser Mort, Baden, PA (US);
William John Murphy, Monroeville, PA (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
The protective relay is primarily energized by a voltage transformer tap on the power circuit. The current transformers that provide the monitoring current to the protective relay also provide an auxiliary power input to the power supply circuit. A switching circuit monitors the input voltage and switches to the current feed to generate the relay supply voltage when the input voltage drops below a predetermined level. In one embodiment the fault tolerant power supply is provided as an optional, modular, add on unit. In a second embodiment, the power supply is an integral part of the protective relay where the current shares a common input between the monitoring and power circuit and the voltage input is common to both the power supply and any metering circuits contained within the protective relay.