Patent ID: 6252488
Filing Date: 2001-06-26
Classification: H01C

Abstract:
A thermal protection device for a metal oxide varistor (MOV) to prevent thermal runaway of said MOV comprising:a) a first segment MOV element defined by a first straight side surface and a first outer side surface;b) a second segment MOV element defined by a second straight side surface and a second outer side surface;c) said first segment and said second segment generally describing a MOV where said first straight side surface is held parallel with said second straight side surface;d) said first segment MOV element and said second segment MOV element heat up when exposed to voltage spikes;e) said first segment having a first front surface and a first rear surface, said second segment having a second front surface and a second rear surface;f) a thermal fusible material layer extending between said first segment first straight side surface and said second segment second straight side surface, said thermal fusible material layer capable of conducting current therethrough and having a predetermined temperature at which it melts and interrupts any flow of current through said thermal fusible material layer;g) a first conductor having a first end and a second end, said first end coupled to one of said first front and first rear surfaces of said first segment, andh) a second conductor having a third end and a fourth end, said third end coupled to one of said second front and rear surfaces of said second segment, whereby current is permitted to flow through said first conductor, said first segment, said thermal fusible material layer, said second segment and said second conductor when said thermal fusible material layer is held below said predetermined temperature and current flow is interrupted when said thermal fusible material layer goes above said predetermined temperature and melts due to the heat provided by said first and second MOV.