Vacuum circuit interrupter contacts and shields
AssigneeWestinghouse Electric Corp.
InventorsRobert L. Thomas, Natraj C. Iyer, Allan J. Bamford, deceased
Life of this patent
Estimating the term…
Abstract
Copper-chromium contacts and copper-ferrous material shields are used in vacuum circuit interrupters. The copper chromium contacts include a specific copper-iron non-abutting section, and an abutting layer preferably of copper-chromium with a layer thickness that constitutes about 50% of the total thickness of the contact which constitutes the abutting section of the contact structure. The shield for the contacts, are preferably formed of copper-ferrous material and "X" in which 1%-50% is ferrous material, and "X"=chromium 0% to 30% and ferrous material plus "X" is less than 60% of the total shield. The contacts and shields are formed by a powder metallurgical procedure.
Claims15
The vacuum type circuit interrupter copper-chromium contact in which said contact includes a copper-iron non-abutting section of the contact formed of copper and iron, and an abutting layer formed of copper and chromium in which said non-abutting section is between 25% to about 50% of the total contact structure, and the abutting layer of copper and chromium forming the rest of the contacts.
The shield, for protecting the inside of a vacuum type circuit interrupter from the erosion products of contacts, in which the shield has a composition of copper, ferrous material, and `X` with `X` being chromium, within a range from 0 to 30% and Fe+`X` being less than 60% of the shield composition.
The method of fabricating the shield for the vacuum type circuit interrupter, in which the steps of fabricating include:
- pouring of Cu-Fe-`X` blend into a die cavity, tapping to level powder, applying a pressure of about 80,000 to about 150,000 psi to form a shield, sintering the shield in a reducing or vacuum furnace at about 950.degree. C. to 1100.degree. C. range for 0.5 to 10 hours, and machining and forming a hollow shield.
The method of fabricating the shield for a vacuum type circuit interrupter, in which the steps are prefabricating a cylindrical shell container or tube container, of copper, or copper alloy, pouring Cu-Fe-`X` powder, in which `X` is chromium, within a range of from 0% to 30% and Fe+`X` being less than 60% of the total shield composition, leveling by tapping or pressing, outgasing the container containing the powder in the 125.degree. to 400.degree. C. range, sealing the container by welding a top cover of the container, welding the top;
- evacuating through a port, sealing the port, hot extruding at 400.degree. to 900.degree. C. range, removing the container and machining the shields.
The vacuum type circuit interrupter comprising a copper-chromium contact in which said contact includes a copper-iron non-abutting section of the contact formed of copper and iron and an abutting layer formed of copper and chromium, in which said non-abutting section is between 25% to about 50% of the total contact structure, and the abutting layer of copper and chromium forming the rest of the contact, and a shield, for protecting the inside of the vacuum type circuit interrupter from the erosion products of the contacts, in which the shield has a composition of copper, ferrous material and `X`0 with `X` being chromium, within a range from 0% to 30% and Fe plus `X` being less than 60% of the shield composition.
Dependencies are inferred from the claim text.