Supersonic expulsion fuse
OwnerWilliam R. Mahieuinventor
Life of this patent
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Abstract
This invention provides a supersonic expulsion fuse for interrupting fault currents in high voltage alternating current networks. It creates an arc interruption region with a long length of supersonic turbulent flow and little or no subsonic plasma. This increases the arc interrupting capability against both thermal and dielectric arc reignitions. Therefore, the transient recovery voltage the network applies across the interrupted arc after current-zero may be increased in both frequency and peak values, relative to present-art expulsion fuses. It may be applied on power distribution systems as a power fuse in enclosures or overhead where the said system transient recovery voltages exceed the capabilities of conventional distribution cutouts.
Claims38
A supersonic expulsion fuse in an ambient dielectric gas for conducting load currents and interrupting fault currents in a high voltage, alternating current network, comprising:
- a. a pair of spaced arc terminating electrodes conductively connected in a current path of said network;
- b. a fusible element conductively bridging said electrodes;
- c. a short length, small cross-sectional area nozzle surrounding a portion of the length of said fusible element, said nozzle having an initial geometry and arc ablation characteristics to remain nearly filled with plasma during most of the arcing period preceding the period of interruption of the highest fault currents said fuse must interrupt;
- d. a pressure chamber effectively sealed over one end of said nozzle, thereby enclosing one of said electrodes, designated the high pressure electrode;
- and
- e. an expansion chamber, effectively sealed over the opposing end of said nozzle and opening to said ambient gas through a flow area greater than said cross-sectional area of said nozzle, and the other electrode of said pair, designated the low pressure electrode, being initially located either inside said expansion chamber or outside it in said ambient gas.
An expulsion fuse for use in a gaseous ambient environment to interrupt current through an alternating current circuit, comprising:
- a housing;
- first and second spaced electrodes in said housing electrically connected to said network to conduct the circuit current therethrough;
- a fusible element electrically coupling said electrodes and initiating the generation of an electrical arc when an overload current is passed therethrough;
- nozzle means for generating a pressurized gas when exposed to an electrical arc, said nozzle means surrounding at least a portion of said fusible element and having first and second opposed ends and a central passageway through which said fusible element passes, said passageway having a preselected length and cross-section;
- a pressure chamber sealing the first end of said nozzle means, and enclosing said first electrode;
- an expansion chamber adjacent the second end of said nozzle opening to said ambient environment, defining a flow area greater than the cross-sectional area of said nozzle means and having a longer length than the length of said nozzle means;
- piston means in said expansion chamber for sealing the second end of said nozzle;
- and
- said second electrode disposed in said expansion chamber.
An expulsion fuse for use in a gaseous ambient environment to interrupt current through an alternating current circuit, comprising:
- a housing;
- first and second spaced electrodes in said housing electrically connected to said network to conduct the circuit current therethrough;
- a fusible element electrically coupling said electrodes and initiating the generation of an electrical arc when an overload current is passed therethrough;
- arc conversion means of arc quenching material located adjacent said first electrode on a first side thereof;
- nozzle means for generating a pressurized gas when exposed to an electrical arc, said nozzle means surrounding at least a portion of said fusible element and having first and second opposed ends and a central passageway through which said fusible element passes, said passageway having a preselected length and cross-section;
- a pressure chamber sealing the first end of said nozzle means, and enclosing said first electrode;
- an expansion chamber adjacent the second end of said nozzle opening to said ambient environment, defining a flow area greater than the cross-sectional area of said nozzle means and having a longer length than the length of said nozzle means;
- piston means in said expansion chamber for sealing the second end of said nozzle;
- said second electrode disposed in said expansion chamber;
- and
- a tubular guide adjacent said expansion chamber, remote from said nozzle means for guiding said piston during an expansion of said pressurized gas in said expansion chamber.
A supersonic expulsion fuse in an ambient dielectric gas for conducting load currents and interrupting fault currents in a high voltage, alternating current network, comprising:
- a plurality of spaced electrodes including a high pressure electrode and a low pressure electrode;
- a fusible element conductively bridging at least two of said electrodes for initiating an electrical arc in response to an overload current;
- a short length, small cross-sectional area nozzle having an internal bore, and an initial geometry and arc ablation characteristics to remain nearly filled with plasma during most of the arcing period preceding the period of interruption of at least some of the fault currents said fuse must interrupt;
- connecting means for conductively connecting the high pressure and low pressure electrodes in a current path of said network extending through said nozzle bore;
- a pressure chamber effectively sealed over one end of said nozzle, enclosing said high pressure electrode;
- and
- an expansion chamber, effectively sealed over an opposing end of said nozzle and opening to said ambient gas through a flow area greater than said cross-sectional area of said nozzle, and the low pressure electrode, being initially located either inside said expansion chamber or outside it in said ambient gas.
Dependencies are inferred from the claim text.