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:
Aug. 03, 1999
Filed:
Apr. 02, 1998
William W Chen, Cedar Rapids, IA (US);
Brett E Larson, Cedar Rapids, IA (US);
Square D Company, Palatine, IL (US);
Abstract
A circuit breaker including a switch having an open and a closed position connected to a line of the circuit breaker. A first actuating device, actuated by a first activating signal, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. A positive temperature coefficient resistivity element (PTC element) is tripped at least once wherein the tolerance of the PTC element is reduced and the PTC element is connected to the first actuating device for providing the first activating signal. In another embodiment of the present invention, a second actuating device, actuated by a second activating signal provided by the circuit breaker current, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. In another embodiment of the present invention, a plurality of PTC elements are tested to determine a tolerance value for each of the PTC elements and at least two of the PTC elements are matched wherein, when the at least two PTC elements are connected in parallel, the combined tolerance is reduced and wherein the ampere rating for the line is increased. In another embodiment of the present invention, the plurality of PTC elements are tripped at least once before testing and matching to further reduce the tolerance of the PTC elements.