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. 21, 2004
Filed:
Sep. 19, 2002
Louis R. Nerone, Brecksville, OH (US);
Joseph C. Oberle, Chagrin Falls, OH (US);
General Electric Company, Schenectady, NY (US);
Abstract
A plurality of lighting ballasts ( ) draw power from a single DC bus signal. A power factor correction circuit ( ) rectifies and smoothes AC power to produce the DC bus signal. In order to prevent damage to the ballast ( ) when a lamp ( ) dies or is removed, the ballast ( ) includes an AC switch that senses damaging conditions and responds by changing a resonant frequency of the ballast ( ). The AC switch operates in 2-3 second cycles. While it is operative, it shunts current away from inductors ( ) of the ballast ( ) causing a resonant frequency of the ballast ( ) to change. At the end of the cycle, the switch turns off, but if a load fault is still present in the ballast ( ) it activates again. Preferably, the AC switch has a response time of approximately 500 &mgr;s.