Patent ID: 6157286
Filing Date: 2000-12-05
Classification: H01H

Abstract:
A current limiting device for limiting the fault current and electrically isolating a load, the current limiting device comprising:an enclosure;a pair of first and second electrically conductive electrodes disposed within the enclosure;at least one current limiting element electrically connected between the electrodes whereby load current passes through said current limiting element and is limited to a predetermined value upon occurrence of an over-current condition, the current limiting element comprising:a polymeric conductor; anda resistive layer, proximate to and in series with the polymeric conductor and the load, having a higher resistivity than the polymeric conductor, whereby the over-current condition causes resistive heating at the resistive layer resulting in rapid thermal expansion and vaporization of the polymeric conductor at said resistive layer causing at least partial separation at said resistive layer thereby causing rapid suppression of the fault current; andat least one spring for providing compression force to the current limiting element, one of said at least one spring being arranged intermediate the enclosure and one of said first and second electrically conductive electrodes.