US 4,052,577 AGranted

Magnetically driven ring arc runner for circuit interrupter

AssigneeI-T-E Imperial Corporation

InventorGerald A. Votta

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Abstract

A single pressure sulfur hexafluoride circuit interrupter is contained in a bottle or elongated, cylindrical housing filled with gas under moderate pressure. The bottle contains arcing and main contacts arranged generally along the axis of the bottle and arranged to separate from one another in the vicinity of a pair of spaced, conductive rings fixed relative to one another, and which serve as arc runners. Each of the rings is connected in series with a respective coil which is wound on the axis of its respective ring and which encircles the cooperating contact and conductors therefor. The coils and the conductive rings create a magnetic field which spins an arc drawn between the spaced short-circuited rings through the sulfur hexafluoride gas, thereby to extinguish the arc. Each short-circuited ring and its respective coil are fixed relative to one another and are contained within a common insulation body in order to withstand the high electrodynamic forces created between the rings and coils during high current interruption. A small, low capacity puffer cylinder is connected to one of the moving contacts in order to produce at least a limited amount of gas motion through the arc space between the open contacts and the fixed rings when the contacts separate. The arcing contacts are arranged to have a blow-off path directed to cause an arc drawn between the contacts to transfer to the spaced conductive rings. In one embodiment of the invention, only a single coil is used to produce a magnetic field for spinning the arc between the spaced rings. The interrupter structure is useful in connection with a vacuum dielectric medium.

A circuit interrupter comprising first and second parallel coaxial rings of conductive material;

said first and second rings having first respective confronting surfaces which are operable to define an arcing gap;
at least said first ring comprising a high conductivity short-circuited turn;
an electrical winding having a given number of turns disposed coaxially with said first and second rings and being positioned adjacent a surface of said first ring which is opposite to its said first surface;
first and second electrical terminals for said circuit interrupter respectively connected to one end of said electrical winding and to said second ring;
the other end of said electrical winding being connected to said first ring;
first and second cooperable contacts connected to said first and second terminals, respectively, whereby, after said first and second contacts open, an arc is produced in said arcing gap between said first and second rings, and said arc between said first and second rings is rapidly rotated around said gap;
and a sealed housing filled with a static dielectric gas under pressure greater than atmospheric pressure for housing said circuit interrupter;
said gap between said first and second rings being at least large enough to withstand the maximum voltage to be applied across said gap after said arc is extinguished;
said first and second rings being relatively massive, thereby to serve as good heat sinks to the localized heat generated by the arc therebetween;
said electrical winding being closely magnetically coupled to said first ring whereby, when arc current flows in series with said winding, a high current is induced in said ring, thereby to produce a magnetic field which is phase-shifted from the arc current, thereby to cause rapid rotation of said arc in said gap, even at low instantaneous current;
said first ring and said winding being rigidly immersed in a potted insulation ring, thereby to be rigidly supported against electrodynamic forces of repulsion between said closely spaced first ring and winding.

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Abstract

Claims15