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:
Jan. 08, 1991
Filed:
Jun. 30, 1989
Thomas Yeh, South Weymouth, MA (US);
Sigma Instruments, Inc., Weymouth, MA (US);
Abstract
The disclosed faulted current indicator senses current in a line having a breaker or fuse, and avoids tripping in response to current inrush signals by producing a trip signal in response to an overcurrent occurring for an overcurrent duration which is inversely related to the magnitude of the overcurrent and is faster than the overcurrent operating time of the breaker or fuse. In one embodiment, this involves operating a current protection device in response to an overcurrent occurring for a second overcurrent duration inversely related to the magnitude of the overcurrent according to a first characteristic, and adjusting the first overcurrent duration to follow a second characteristic having variations substantially the same as the first characteristic but having a shorter first overcurrent duration than the second overcurrent duration.