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:
Feb. 11, 1997
Filed:
Aug. 18, 1994
ABB Research Ltd., Zurich, CH;
Abstract
The electrical resistance element (10) includes a resistance body (3), which is arranged between two plane-parallel, pressurized electrodes (1, 2), has PTC behavior and comprises a polymer matrix and two filler components of electrically conducting particles embedded into the polymer matrix (4). When a short-circuit current occurs, the resistivity of the resistance body (3) changes abruptly above a temperature limit value in a surface layer resting on the electrodes and containing at least a first of the two filler components. A second of the two filler components is selected such that a composite material containing at least the polymer matrix and the second filler component has PTC behavior, with an abruptly changing behavior greater by at least one order of magnitude in comparison with the surface layer. At the same time, this composite material has a resistivity which is lower by at least one order of magnitude than a composite material formed by the polymer matrix and the first filler component. The resistance element has a high nominal current carrying capacity and can limit large short-circuit currents permanently.