Shape memory alloy trip mechanism for arc/ground fault circuit interruption

Abstract

A miniature circuit breaker comprising a non-conductive housing assembly; a pair of separable contacts including a first, fixed contact coupled to said housing assembly and having a terminal extending outside said housing assembly, and a second, movable contact having a terminal extending outside said housing assembly; an operating mechanism coupled to, and structured to move, said movable contact between a first position, wherein said movable contact engages said fixed contact, and a second position, wherein said movable contact is spaced from said fixed contact; a trip device coupled to said operating mechanism and structured to actuate said operating mechanism to separate said separable contacts upon the occurrence of a trip condition; an arc fault trip mechanism having an arc fault detector and a shape memory alloy element; said arc fault detector structured to detect an arc fault on the load side of said separable contacts and to provide an electrical pulse; said shape memory alloy element structured to transform between a first shape and a second shape during the application of an electrical pulse, said shape memory alloy element having a first end and a second end, said shape memory alloy element first end coupled to said housing assembly, said shape memory alloy element coupled to said trip device; said arc fault detector further coupled to said shape memory alloy element and structured to provide an electrical pulse to said shape memory alloy element sufficient to transform said shape memory alloy element from said first shape and said second shape; and wherein when said shape memory alloy element is in said second shape, said trip device is actuated and said operating mechanism separates said separable contacts.