Westinghouse Electric Corporation

Sidney J Cherry

Paul O Wayland

Robert M Hruda

Alan T Male

Natraj C Iyer

Richard A White

George R Turner

Robert E Gainer

A powdered metallurgical procedure for forming chromium copper contacts used in vacuum circuit interrupters, in which prealloyed powder formed by mixing to copper, chromium of between two to thirty-seven weight percent is rapidly solidified after melting at about 1100.degree. C. to 1500.degree. C. This powder may be blended with additional chromium of between 12 to 50 weight percent with a maximum of fifty-five weight percent of chromium in the final contact structure. This blended mixture may then be either (i) cold pressed at 100,000 psig. and vacuum sintered at 800.degree. to 1400.degree. C.; or (ii) be subjected to hot isostatic pressure of 10,000 to 30,000 psig. at between 700.degree. C. to 1080.degree. C.; or (iii) containing the blended copper-chromium powder and the additional chromium powder into an evacuated can and hot extruding the can between 400.degree. C. to 900.degree. C., to form the contacts.

Vacuum circuit interrupter contacts containing chromium dispersions

A retainer member formed from wire or sheet metal secures the movable contact rod guide bushing to the end plate closure of a vacuum interrupter.

Vacuum interrupter guide bushing retainer means

The present invention is directed to a cup type vacuum interrupter contact comprised of a holder portion and a contact portion. The holder portion is cup shaped and has a base and side walls extending vertically from the base. The contact portion is circular in configuration corresponding approximately in shape and cross-sectional area to the side walls of the holder portion and is disposed on and affixed to the rim of the side walls. The holder portion has slots extending at an angle from its base through the side walls to the rim. The holder portion is comprised of a precipitation-hardened copper alloy and the contact portion is comprised of copper.

Cup type vacuum interrupter contact

A vacuum interrupter electrical contact which exhibits an improved voltage withstand characteristic. The electrical contact comprises a minor portion of selected refractory metal and a major portion of dispersion strengthened copper.

Vacuum interrupter contact material

An improved vacuum interrupter structure with a unitary end closure and end seal shield member which is sealed to the end of the generally cylindrical body of the interrupter. This member performs the function of sealing the generally cylindrical body at the opposed ends, and also to shield the seal area from hot material which may evolve from the contacts during contact opening. The resultant end shield structure provides an improved breakdown voltage characteristic for the interrupter.

Unitary end closure and seal shield member for vacuum interrupter

A vacuum interrupter contact structure in which central butt-type contacts serve as the load current carrying contacts with low resistive losses. Annular transfer arcing contacts are disposed coaxial about the butt-type contacts, with the arc which forms during interruption moving out to these arcing contacts. Axial magnetic field generating means are associated with the transfer arcing contacts to maintain a diffuse arc during interruption.

Vacuum interrupter with transfer-type axial magnetic field contacts

An improved low voltage, high current D.C. vacuum switch is provided by disposing an arcing shield annularly about the arcing contact area within the vacuum switch. The arcing shield prevents disposition of conductive contact material on the insulator body wall of the switch and also shields the flexible corrugated annular member which permits switch contact movement to open and close the switch. The arcing shield may be floating electrically, or connected to the electrically positive side of the switch contacts.

Low voltage vacuum switch with internal arcing shield

A vacuum-type circuit interrupter is provided having a two-material vapor, or condensing shield for providing a high-conductivity material, such as copper, for the part that is exposed to the arc, and a superior high-voltage material, such as stainless steel, for the ends of the vapor or condensing shield. Preferably, since the ends of the vapor shield are the origins of high-electric-field intensity, which may result in arcing in a vacuum, to avoid this, a superior high-voltage material, such as stainless steel, is provided.

Two-material vapor shield for vacuum-type circuit interrupter

A vacuum-type circuit interrupter has a condensing shield which is maintained at a predetermined potential relevant to the separable contacts by the use of resistance means, which are tapped off to the condensing shield. The resistance means may assume either the form of a surface coating with a preselected resistance on the inside or the outside of the insulating envelope casing, or the resistance means could be a ceramic envelope casing having a preselected volume resistance. Additionally, the use of coatings of metals and/or semiconductors on the inside and/or the outside of the insulating envelope casing may be used to obtain the desired preselected surface resistance values. Even external circuitry, connected to the condensing shield and the contacts, may be used to achieve the proper resistance values. The foregoing arrangements prevent the condensing shield from 'floating' in potential value relevant to the separable electrodes, and gives rise to desirable results.

Vacuum-type circuit interrupters with condensing shield at a fixed

A power vacuum fuse using coaxial electrodes with the fuse length disposed therebetween. In one embodiment of the invention a larger diameter outer cylinder is partially disposed around a hollow inner cylinder within an evacuated chamber and the fuse links are connected from the inner cylinder to the outer cylinder. The inner cylinder can have spiral or slots formed therein to move the arc as desired. In another embodiment of the invention a solid inner cylinder is disposed within a hollow diameter outer cylinder, which can form or be directly connected to a metallic enclosure. Current paths can be provided into the solid inner cylinder from both ends, thus substantially increasing the current carrying capacity of a given size vacuum fuse. In yet another embodiment of the invention a hollow inner cylinder is partially disposed within a larger diameter outer cylinder. The inner cylinder is connected at one end to a terminal means and the free end thereof has an outward radially extending lip which extends into a folded back hollow cylindrical portion from the inner diameter portion. Thus the hollow inner cylinder provides for an elongated current path in a direction to reduce some magnetic force.

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Elmira, NY, United States of America

Sidney J Cherry