Voltage surge limiter with grounding assembly

An electrical protector assembly for protecting a circuit against excessive current increases and voltage surges, said protector assembly including:

• a dielectric housing supporting the assembly;
• a grounding subassembly for grounding said protector assembly when excessive voltage surges and excessive current increases occur in the circuit;
• a voltage protection subassembly including a gas tube assembly which comprises first and second electrodes spaced apart through a relatively wide primary gap filled with a gas at a predetermined pressure and disposed within a metallic container having a closed end and an open end with the container being connected electrically to said grounding subassembly and with said second electrode being in engagement with said closed end of said container;
• a current protection subassembly including a shunting element, first and second electrically conductive elements and a dielectric base for supporting said first and second electrically conductive elements which are connected to said shunting element to establish electrical contact between the circuit and said protector assembly, said shunting element being movably mounted and supported by a fusible material in a predetermined position along said first electrically conductive element in axial alignment therewith and in engagement with said voltage protection subassembly;
• and
• energy storage means interposed between said voltage protection subassembly and said housing and removed from a current path between said voltage protection and grounding subassemblies for maintaining said voltage protection subassembly in electrical engagement with said shunting element, and which is effective upon melting of the fusible material caused by the flow of current above a predetermined level for causing said shunting element to be moved along said first electrically conductive element from a first position to a second position to engage said grounding subassembly and provide a current path from said first element to said grounding subassembly;
• and characterized in that
• an annular metallic member and an annular dielectric member are interposed between said container and said first electrode, said dielectric member having at least one aperture therethrough to define an auxiliary gap which is substantially less than said primary gap, said annular metallic member being retained within said open end of said container by forces directed toward said closed end which cause the pressure between said annular metallic member and said annular dielectric member to be substantially constant, and said electrodes and said container being adapted to be moved by said energy storage means without relative movement therebetween when said fusible material is melted and said shunting element is moved along said first electrically conductive element.

A gas tube assembly, said gas tube assembly including;

• a metallic container having a closed end and an open end, said open end having inwardly directed side portions;
• an insulative sleeve disposed within said metallic container;
• first and second electrodes with said second electrode being attached to one end of said sleeve and being in engagement with said closed end of said container, and with said first electrode being attached to another end of said sleeve, said first and second electrodes being spaced apart within said sleeve through a relatively wide primary gap;
• and characterized in that
• said assembly includes spacer means for spacing said first electrode from said inwardly directed side portions at said open end, said spacer means including an annular metallic member which is in engagement with said inwardly directed side portions and an annular dielectric member which is interposed between said annular metallic member and said first electrode, said annular dielectric member having at least one aperture therein which is confronted by said annular metallic member and which has a thickness predetermined to provide a desired auxiliary gap, said closed end of said container being formed with a depressed portion to cause said inwardly turned side portions to be biased toward said closed end to cause said spacer means to be in engagement with said first electrode and with said inwardly turned portions at a substantially constant pressure.