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. 30, 1995
Filed:
Dec. 21, 1992
Edmund O Schweitzer, Jr, Northbrook, IL (US);
Other;
Abstract
A fault indicator for indicating at local and remote locations the occurrence of a fault current in a conductor of an AC power distribution system utilizes a liquid crystal display having independent 'F' and 'N' optical display and shutter elements. Upon occurrence of a fault current a reed switch closes and a portion of the charge on a first capacitor is transferred to a second capacitor, which is connected to the 'F' actuator electrodes of the liquid crystal display to cause an 'F' to be displayed and an associated optical shutter to open. The 'N' actuator electrodes are capacitively coupled to the monitored conductor and system ground to cause an 'N' to be displayed and an associated optical shutter to open to indicate that voltage is present on the conductor. First and second light sources are caused to project through respective ones of the optical shutters onto respective first and second photodetectors. A first control circuit responsive to the output of the first photodetector provides a first output signal indicative of the occurrence of a fault. A second control circuit responsive to the second photodectector provides a second output signal indicative of the presence of voltage on the conductor.