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. 12, 1991
Filed:
Sep. 21, 1990
Alexander Kusko, Needham Heights, MA (US);
Noshirwan K Medora, North Attleborough, MA (US);
Other;
Abstract
A ground fault detector has a neon bulb connected between a rectangular copper plate connected to an antenna wire and a resistor connected to one arm of a double-pole double-throw relay with the stationary contacts cross coupled to hot and neutral wires of a three-wire A.C. line. A photocell detector is optically coupled to the neon bulb and provides a signal to a live wire detector circuit when the neon bulb is illuminated to disable operation of the relay. A timer circuit causes the live wire detector circuit to operate the relay when the neon bulb is not illuminated after a predetermined time. A network is photo-optically coupled to a ground status detector that controls a contactor that selectively connects power to the equipment being monitored. The junction of a Y network is also coupled to the input of the ground status detector. The input of the photo-optical coupler is connected between a leg of the Y circuit and the enclosure of the equipment being monitored. Another leg of the Y network is connected to the enclosure of the equipment being monitored.