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:
Jul. 07, 2009
Filed:
Jul. 08, 2004
Wojciech Piasecki, Cracow, PL;
Marek Florkowski, Cracow, PL;
Mariusz Luto, Bialystok, PL;
Pentti Mahonen, Vaasa, FI;
Wojciech Piasecki, Cracow, PL;
Marek Florkowski, Cracow, PL;
Mariusz Luto, Bialystok, PL;
Pentti Mahonen, Vaasa, FI;
ABB Research Ltd., Zurich, CH;
Abstract
A protection system for a transformer system that includes three single phase transformers with auxiliary secondary windings, respectively. The auxiliary secondary windings are connected to form an open delta configuration. The protection system is connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers. The protection system includes a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.