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US 5,382,938 AGranted
PTC element
AssigneeAsea Brown Boveri AG
InventorsTomas Hansson, Per-Olof Karlstrom
Life of this patent
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AssigneeAsea Brown Boveri AG
InventorsTomas Hansson, Per-Olof Karlstrom
Estimating the term…
A PTC element has at least one body and two electrodes. The body or bodies has/have and is/are two parallel surfaces, of an electrically conductive polymer composition with a positive temperature coefficient. At least one of the parallel surfaces on the body, or on one of the bodies, of polymer composition is in free contact with an electrode or with a parallel surface on another body of electrically conductive polymer composition. A pressure device exerts a pressure directed perpendicularly to the parallel surfaces on the body, or the bodies, on the electrodes. The pressure device is preferably provided with pressure-exerting devices with the ability to be resilient. After changing from a low resistance to a high resistance state, the PTC element returns to the initial resistance and is reusable after having been subjected to short-circuit currents. The parallel surfaces on the body, or the bodies, of polymer composition may be concentric.
A PTC element comprising a body of an electrically conductive polymer composition having a positive temperature coefficient, said body defining two parallel surfaces;
A PTC element comprising at least two bodies, each provided with two parallel surfaces of electrically conductive polymer compositions with a positive temperature coefficient in which one of the parallel surfaces on the body of polymer composition and one of the parallel surfaces on the other body included in the PTC element are arranged in electrical contact with electrodes included in the PTC element for carrying current through the bodies of polymer composition, wherein at least one of the bodies of polymer composition has at least one of its parallel surfaces in free contact with one of the parallel surfaces of one other body of polymer composition, and including a pressure device which presses the electrodes against the bodies in a direction perpendicular to the parallel surfaces on the bodies of polymer composition, said pressure device applying a pressure of at least 14.5 psi on said electrodes.
Dependencies are inferred from the claim text.