Transient suppression system

Claim 1

An electrical protective system for protecting an electrical circuit against undesired, temporary high voltage electrical signals, said system being adapted to be connected in shunt across the input of the circuit to be protected, comprising a spark gap device including a pair of spaced electrodes adapted to support an electrical discharge therebetween in response to a preselected voltage level established thereacross as a result of the occurrence of an undesired, temporary high voltage, transient signal in excess of said preselected voltage level so as to define a relatively high current capacity path between its electrodes for shunting transient signals in excess of said preselected voltage level from the circuit being protected, and a ballast resistor serially connected to said spark gap device for harmlessly and rapidly dissipating the energy of said transient signal thereacross to protect said spark gap device against excessive heating and for limiting the current passing between the electrodes of said voltage breakdown device subsequent to the establishment of the electrical discharge so as to effect extinguishment thereof subsequent to the expiration of the transient signal, said ballast resistor having a resistance which increases responsive to current flow therethrough and associated energy dissipation thereacross so that a relatively low resistance value is presented upon the initial establishment of the electrical discharge to facilitate dissipation of substantially all of the energy of the transient signal thereacross resulting in a substantially increased resistance level sufficient to limit subsequent current flow therethrough to a level below that required for maintaining the electrical discharge across the spark gap electrodes.

Claim 6

A system for selectively shunting and dissipating high voltage electrical transient signals to protect an electrical network, said system comprising a spark gap device connected in shunt with the circuit to be protected, said spark gap device including a pair of spaced electrodes adapted to support an electrical arc therebetween in response to the establishment of a preselected voltage level between said electrodes due to the occurrence of a transient signal in excess of said preselected voltage level, and a ballast impedance serially connected to said spark gap device for substantially completely dissipating the energy of the transient signal to protect said spark gap device against excessive heating, said ballast impedance having a resistance which increases responsive to current flow therethrough and associated energy dissipation thereacross so that a relatively low resistance level current path initially is provided for the transient signal upon the establishment of the electrical arc to facilitate dissipation of substantially all of the energy of the transient signal across said ballast impedance resulting in a substantially increased resistance level, said ballast impedance including a filament of essentially pure tungsten having a preselected length and a preselected thickness sufficient to dissipate the energy of the transient signal and to limit subsequent follow-on current as a result of the increased resistance thereof due to heat generation so as to effect extinguishment of the electrical arc rendering the spark gap device non-conductive subsequent to the expiration of the transient signal.

Claim 7

A system for selectively shunting and dissipating high voltage electrical transient signals to protect an electrical network, said system comprising a spark gap device connected in shunt with the circuit to be protected, said spark gap device including a pair of spaced electrodes adapted to support an electrical arc therebetween in response to the establishment of a preselected voltage level between said electrodes due to the occurrence of a transient signal in excess of said preselected voltage level, and a ballast impedance serially connected to said spark gap device for substantially completely dissipating the energy of the transient signal to protect said spark gap device against excessive heating, said ballast impedance having a resistance which increases responsive to current flow therethrough and associated energy dissipation thereacross so that a relatively low resistance level current path initially is provided for the transient signal upon the establishment of the electrical arc to facilitate dissipation of substantially all of the energy of the transient signal across said ballast impedance resulting in a substantially increased resistance level, said ballast impedance including a filament of essentially pure tungsten having a preselected length and a preselected thickness sufficient to dissipate the energy of the transient signal and to limit subsequent follow-on current as a result of the increased resistance thereof due to heat generation so as to effect extinguishment of the electrical arc rendering the spark gap device non-conductive subsequent to the expiration of the transient signal.