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:
Sep. 29, 2009
Filed:
Dec. 07, 2007
Frederick A. Stich, Wisconsin Rapids, WI (US);
James H. Harlow, Mentone, AL (US);
William F. Griesacker, Moon Township, PA (US);
Reshma Sharif, Pittsburgh, PA (US);
Frederick A. Stich, Wisconsin Rapids, WI (US);
James H. Harlow, Mentone, AL (US);
William F. Griesacker, Moon Township, PA (US);
Reshma Sharif, Pittsburgh, PA (US);
Pennsylvania Transformer Technology, Inc., Canonsburg, PA (US);
Abstract
A load tap changer includes a single mechanical switch that is movable to create, in a first position, a first conducting path between a first transformer tap and a load. When the switch is in a second position, the switch creates a second conducting path between a second transformer tap and the load. A first thyristor pair or other device creates a first alternate conducting path between the first transformer tap and the load when the switch is disengaged from the first position. A second thyristor pair or other device creates a second alternate conducting path between the second transformer tap and the load when the mechanical switch is disengaged from the second position. Each thyristor pair may be selectively triggered to provide a conducting path when voltage across either thyristor pair exceeds a predetermined level. A gate trigger circuit may be included for each thyristor pair, and a gate control circuit may control each of the gate trigger circuits.