Patent ID: 6429766
Filing Date: 2002-08-06
Classification: H01C

Abstract:
An electrical device for overcurrent fault and short-circuit current fault protection, comprising:a PTC polymer element; electrical contacts applied to the PTC polymer element and defining a main direction of current flow in a section of the PTC polymer element, the section of the PTC polymer element comprising first and second holes arranged to form a constriction of PTC polymer between the first and second holes and extending in the main direction of current flow, wherein; the first hole comprises a first surface parallel to the main direction of current flow, the first surface forming a first boundary of the constriction; the second hole comprises a second surface parallel to the main direction of current flow, the second surface forming a second boundary of the constriction; and the portion of the constriction between the first and second surfaces has a minimum cross-sectional area of the constriction and extends in the main direction of current flow over a length of at least 5 millimeters.