| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum circuit breaker equipped with a vacuum valve of excellent current breaking characteristics through stabilization of re-arcing characteristics of a contact point alloy. SOLUTION: With the vacuum circuit breaker equipped with a detachable pair of conductive shafts penetrated into a vacuum vessel, a detachable pair of opposing contacts with one end bonded to the conductive shaft, and a vacuum valve having, as is needed, an arc shield, the contact points are composed of a conductive ingredient, arc-resistant ingredient, and an auxiliary ingredient added as is necessary, and total volume of gas molecules whose mass number included in total sum of gas molecules contained in the contact points (ΣGas) is not less than 39 (ΣM/Z>=39) is 1.0×10<-5> volume percent to 1.0×10<+1> volume percent, so that, it is possible to provide a vacuum circuit breaker equipped with a vacuum valve of excellent current breaking characteristics by stabilizing re-arcing characteristics of a contact point alloy.
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