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:
Dec. 04, 1990
Filed:
Mar. 10, 1989
Youichi Oshita, Katsuta, JP;
Akira Hashimoto, Hitachi, JP;
Yukio Kurosawa, Hitachi, JP;
Yoshiaki Inui, Ibaraki, JP;
Tokio Yamagiwa, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A contact abnormality detection system for use in a gas-insulated switchgear or other power transmission or distribution apparatus. A gas-insulated switchgear includes a hermetic housing, an insulating gas sealed in the housing, and conductors in the housing having contacts for providing a path for a large current and being electrically insulated from the housing. An abnormality in the contacts causes the contacts to generate vibrations when a large current flows through them. A vibration detector detects vibrations generated by the switchgear including the vibrations generated by the contacts. The frequency spectrum of the vibrations detected by the vibration detector is analyzed to detect if the vibrations contain frequency components in the range of 200 to 500 Hz which meet predetermined criteria. If the vibrations do contain such frequency components, a contact abnormality decision unit decides that the contacts exhibit a contact abnormality, thereby permitting the abnormality to be identified before the contacts fail.