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:
Feb. 11, 2003
Filed:
Jan. 29, 2001
Applicant:
Inventors:
Rainer Frotscher, Regenstauf, DE;
Dieter Dohnal, Lappersdorf, DE;
Assignee:
Pharmacia & Upjohn Company, Kalamazoo, MI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 3/112 ; G01R 3/102 ; H01H 1/958 ;
U.S. Cl.
CPC ...
G01R 3/112 ; G01R 3/102 ; H01H 1/958 ;
Abstract
A method of monitoring contact burnoff in tap changers operating under load in which the load current is measured and for nominal variation of the voltage of the particular tap parameters are stored which are used to calculate the burnoff rate per contact per switching operation. From these values the cumulative burnoff rate of both the switching contact and resistance contact are determined and compared with limits or threshold values.