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:
Oct. 02, 1984
Filed:
Jul. 27, 1981
Douglas M Mattox, Pittsburgh, PA (US);
Tapan K Gupta, Pittsburgh, PA (US);
William G Carlson, Murrysville, PA (US);
Shih M Ho, Pittsburgh, PA (US);
Electric Power Research Institute, Palo Alto, CA (US);
Abstract
A non-linear voltage limiting device displaying a particular stability characteristic and designed to eliminate flashover failure across its circumferential edge is disclosed herein along with a specific method of fabrication. The voltage limiting device is characterized by a rising resistive current with time at predetermined temperature and voltage levels and includes a disc-shaped wafer composed primarily of zinc oxide. In accordance with the method disclosed herein, after this wafer is formed and sintered in accordance with prescribed temperature and time requirements, its circumferential edge is provided with an anti-flashover coating which requires curing. Thereafter, the coated wafer is annealed in a way which cures the coating and, at the same time, reduces and preferably minimizes the resistive current rise characteristic referred to above.