To improve cutoff performance by providing a discontinuous portion in the composition change of components at least at one (r) section when the relation y=f(r) is satisfied between the component quantity (y) of the arc- resistant component and the distance (r) from the contact point center.
Contact points for a vacuum valve with the radius R having the same component composition for the same radius contain the conductive component, arc-resistant component, and auxiliary component as required. When the relation y=f(r) is satisfied between the component quantity y(0≤y≤1) of the arc-resistant component and the distance (r) from the contact point center, a discontinuous portion in the component composition change is provided at least at one position in 0≤r≤R on the figure of y=f(r) drawn on the r-y plane. The arc occurring at the time of a cutoff is moved on the contact point without being retained and concentrated at the portion having a low arc voltage, the diffusion of the arc is accelerated, and the cutoff performance can be improved.
KUSANO TAKASHI
SEKI KEISEI
YAMAMOTO ATSUSHI
SEKIGUCHI SHIGEAKI
TOSHIBA CORP
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