Abstract: A contact material for use in a vacuum circuit interrupter which simultaneously provides superior current interrupting performance and breakdown voltage. The contact material of the invention includes components of copper, tantalum and at least one of cobalt and iron. Cobalt or iron should be present in an amount of 50 wt % or less, while the combination of tantalum and cobalt or iron should be present in an amount of at least 10 wt %. A fourth component of at least one of titanium, zirconium and aluminum may be added. Also, there may be included a fifth component containing at least one of a low melting point metal, alloys of a low melting point metal, intermetallic compounds of a low melting point metal, and oxides thereof, with the low melting point metal being at least one of bismuth, tellurium, antimony, thallium, lead, selenium, cerium and calcium in an amount of not more than 20 wt %.

Abstract: The disclosed electrode composition for a vacuum switch comprises copper, as a principal ingredient, a low melting point metal such as Bi, Pb, In, Li, Sn or any of their alloys, in a content not exceeding 20% by weight, a first additional metal such as Te, Sb, La, Mg or any of their alloys and a refractory metal such as Cr, Fe, Co, Ni, Ti, W or any of their alloys in a content less than 40% by weight.

Abstract: The disclosed electrode composition for a vacuum switch comprises copper, as a principal ingredient, a low melting point metal such as Bi, Pb, In, Li, Sn or any of their alloys, in a content not exceeding 20% by weight, a first additional metal such as Te, Sb, La, Mg or any of their alloys and a refractory metal such as Cr, Fe, Co, Ni, Ti, W or any of their alloys in a content less than 40% by weight.

Abstract: A contact for a vacuum circuit breaker is disclosed which contains copper as a first component and also at least two elements of the group of chromium, molybdenum, and tungsten as the other components. Each of these other components is contained in an amount not greater than 40% by weight.

Abstract: The disclosed windmill-shaped electrode comprises a central circular flat portion, a tapered portion connected to the central flat portion to encircle it and four circular arc-shaped slots extending radially and circumferential through the tapered portion and terminating at the flat portion. The flat portion has a radius not smaller than 0.4 time and not larger than 0.7 time a maximum radius of the electrode. Each slot describes a circular arc having a single radius not smaller than the radius of the flat portion.