Patent ID: 6144540
Filing Date: 2000-11-07
Classification: H01C,H01H,H02H

Abstract:
A current suppressing circuit breaker unit comprising:a circuit breaker housing;at least one pair of circuit breaker contacts within said circuit breaker housing for interrupting circuit current;an operating mechanism within said circuit breaker housing for separating said circuit breaker contacts;a trip unit within said circuit breaker housing for articulating said operating mechanism to separate said circuit breaker contacts upon the occurrence of an overcurrent condition in a protected circuit;a current limiting element electrically connected with said at least one pair of circuit breaker contacts whereby circuit current passes through said current limiting element and becomes limited to a predetermined value upon occurrence of said overcurrent condition, said current limiting element comprising:a polymeric conductor; anda resistive layer, proximate to and in series with said polymeric conductor in said protected circuit, having a higher resistivity than said polymeric conductor, whereby said overcurrent condition causes resistive heating at said resistive layer resulting in rapid thermal expansion and vaporization of said polymeric conductor at said resistive layer causing at least partial separation at said resistive layer thereby causing rapid suppression of said circuit current;first and second electrically conducting electrodes, said first electrode being electrically connected between said at least one pair of circuit breaker contacts and said current limiting element, and said second electrode being electrically connected between said current limiting element and the protected circuit; anda spring arranged to force said first electrically conducting electrode towards said second electrically conducting electrode for compressing said current limiting element.