Abstract: The flux density Bct is applied at the center area of the electrode. The flux density Bct is adjusted within the range A of 0.75 to 0.9 times greater than the axial flux density Bcr which gives the lowest arc voltage between the electrodes against each breaking current. The axial flux density monotonously increases from the center to the circumferential area of the electrode. Here, the radial position where the axial flux density Bcr which gives the lowest arc voltage Vmin is adjusted within the region B of 20% to 40% of the radius of the electrode. The axial flux density is made monotonously increase in an outer area from the region B and give the maximum value Bp in a circumferential area equal to or beyond 70% of the radius of the electrode. The maximum value Bp is adjusted within the range C of 1.4 to 2.4 times greater than the flux density Bct given at the electrode center.

Abstract: The flux density Bct is applied at the center area of the electrode. The flux density Bct is adjusted within the range A of 0.75 to 0.9 times greater than the axial flux density Bcr which gives the lowest arc voltage between the electrodes against each breaking current.

Abstract: A method for improving flux density in a vacuum valve, includes producing, with a vacuum valve, an axial magnetic field parallel to an arc generated between a movable and a stationary electrodes facing each other, and adjusting a magnitude of an axial flux density between the electrodes to increase gradually from a center area of the electrodes toward a circumferential area of each electrode. A point gives a maximum value (Bp) of the axial flux density at a location of and beyond 70% of a radius from the center of each electrode, and the maximum value (Bp) of the axial flux density in a radial line from the center to a circumferential end to be 1.4 to 2.4 times greater than a flux density of the center Bct of each electrode.

Abstract: The flux density Bct is applied at the center area of the electrode. The flux density Bct is adjusted within the range A of 0.75 to 0.9 times greater than the axial flux density Bcr which gives the lowest arc voltage between the electrodes against each breaking current.

Abstract: A method for manufacturing a vacuum interrupter including, a vacuum enclosure composed of an insulating tube sealed by metal flanges, a pair of electrodes in the vacuum enclosure which are able to make and break contact, and a pair of conducting shafts.

Abstract: A contact material for a vacuum interrupter includes: (a) from 25 to 70% by volume of a highly conductive component selected from the group consisting of Ag, Cu and combinations thereof, and (b) from 30 to 75% by volume of an arc-proof component comprising a carbide of an element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and combinations thereof, wherein the average grain size of the said arc-proof component is from 0.3 to 3 micrometers and the average grain distance of the arc-proof component is within the range of 0.1 to 1 micrometer. Contacts for a vacuum interrupter obtained from the contact material have improved wear resistance, large current interruption characteristic, wear resistance, and chopping characteristic, and low temperature rise characteristic.

Abstract: An Ag-Cu-WC contact forming material for a vacuum interrupter comprising a highly conductive component comprising Ag and Cu and an arc-proof component comprising WC wherein the content of the highly conductive component is such that the total amount of Ag and Cu(Ag+Cu) is from 25% to 65% by weight and the percentage of Ag based on the total amount of Ag and Cu[Ag/(Ag+Cu)] is from 40% to 80% by weight; wherein the content of the arc-proof component is from 35% to 75% by weight; wherein the structure of the highly conductive component comprises a matrix and a discontinuous phase, the discontinuous phase having a thickness or width of no more than 5 micrometers and wherein said arc-proof component comprises a discontinuous grain having a grain size of no more than 1 micrometer.

Abstract: A vacuum breaker contact produced according to the coating step of forming a metal coated layer comprising at least one metal selected from the group consisting of Cu, Ag, Ni, Sn, In, Fe and alloys thereof on at least a part of the surface of the contact substrate having a predetermined shape to a thickness of 10 .mu.m or less, and the diffusion step of having a part of the metal coated layer diffused into the contact substrate.

Abstract: A contact forming material for a vacuum interrupter comprising: from 25% to 65% by weight of a highly conductive component comprising Ag and Cu, and from 35% to 75% by weight of an arc-proof component selected from the group consisting of Ti, V, Cr, Zr, Mo, W and their carbides and borides, and mixtures thereof wherein the highly conductive component of the contact forming material comprises (i) a first highly conductive component region composed of a first discontinuous phase having a thickness or width of no more than 5 micrometers and a first matrix surrounding the first discontinuous phase, and (ii) a second highly conductive component region composed of a second discontinuous phase having a thickness or width of at least 5 micrometers and a second matrix surrounding the second discontinuous phase, wherein the first discontinuous phase in the first highly conductive component region is finely and uniformly dispersed in the first matrix at intervals of no more than 5 micrometers, and wherein the amount of

Abstract: A vacuum breaker contact produced according to the coating step of forming a metal coated layer comprising at least one metal selected from the group consisting of Cu, Ag, Ni, Sn, In, Fe and alloys thereof on at least a part of the surface of the contact substrate having a predetermined shape to a thickness of 10 .mu.m or less, and the diffusion step of having a part of said metal coated layer diffused into said contact substrate.