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:
Apr. 09, 2013
Filed:
Aug. 27, 2008
Oliver Brueckl, Waldmunchen, DE;
Dieter Dohnal, Lappersdorf, DE;
Hans-henning Lessmann-mieske, Neutraubling, DE;
Oliver Brueckl, Waldmunchen, DE;
Dieter Dohnal, Lappersdorf, DE;
Hans-Henning Lessmann-Mieske, Neutraubling, DE;
Maschinenfabrik Reinhausen GmbH, Regensburg, DE;
Abstract
An on-load tap changer with semiconductor IGBT switching elements for uninterrupted switching over between winding taps of a tapped transformer, has two load branches connectable with the respective winding taps and each load branch is electrically connected with a common load output line through a respective series circuit consisting of two oppositely connected IGBTs. A diode is connected parallel to each IGBT, and the two diodes in each load branch are connected oppositely to one another. A respective mechanical switch is connected in series with the series circuit of IGBTs and parallel diodes in each load branch. A respective varistor is connected parallel to each parallel circuit of IGBT and diode, and the varistors are so dimensioned that the respective varistor voltages are lower than the maximum blocking voltage of the respective parallel IGBTs but higher than the maximum instantaneous value of the tap voltage.