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. 03, 2012
Filed:
May. 08, 2009
John Foster Farrow, Plymouth, MI (US);
John Foster Farrow, Plymouth, MI (US);
Welding Technology Corporation, Farmington Hills, MI (US);
Abstract
The invention is a simple amplifier circuit for a current transformer to measure very small AC currents, as required for ground fault detection. The circuit presents a very low impedance to the current transformer output and provides high amplification of the current transformer signal. Concurrently and with no additional components, the inventive circuit supplies a bias current to the current transformer to improve its performance and provides output signals which can be used to detect disconnection of the current transformer or a short circuit between either of the current transformer terminals and ground.