Patent ID: 6107582
Filing Date: 2000-08-22
Classification: H01H

Abstract:
A vacuum valve having a contact material consisting of a constituent of high electrical conductivity comprising at least one of Cu or Ag, an anti-arcing constituent comprising Cr in which particles whose particle size is in the range 0.1.about.150 .mu.m represent at least 90 volume % of the total particles, wherein:a ratio defined by the formula (.alpha..sub.900 -.alpha..sub.50).times.100/(.alpha..sub.900) for said contact material has a value of at least 0.8% and less than 12% wherein .alpha..sub.900 is the value of the coefficient of thermal expansion of said contact material at 900.degree. C. and .alpha..sub.50 is the value of the coefficient of thermal expansion of said contact material at 50.degree. C.