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. 30, 2014
Filed:
Jan. 22, 2013
Zoran Gajic, Vasteras, SE;
Zoran Gajic, Vasteras, SE;
ABB Technology AG, , CH;
Abstract
An arrangement to detect a ground fault in an AC electric circuit including an electric machine having a neutral point connecting to a neutral point and a terminal side, and a unit transformer connected to the terminal side of the machine, wherein the arrangement includes a signal injection unit, a voltage transformer having a primary winding connected to the terminal side of the electric machine and a secondary winding that is open delta-connected, an instrument transformer having a primary winding connected to the neutral point of the electric machine and a secondary winding, and a ground fault detecting unit. The signal injection unit is configured to inject a signal to the secondary winding of the voltage transformer. The instrument transformer is configured to measure the resultant injected signal at its secondary winding The ground fault detecting unit is configured to detect a ground fault based on the measured signal.