| 摘要 |
PROBLEM TO BE SOLVED: To improve a structure of a mold case so as to improve breaking performance and reliability by suppressing insulation degradation caused by adhesion of a metal molten material produced with current cutoff to a switching mechanism or the like and intrusion of an arc gas between electrodes. SOLUTION: This circuit breaker is assembled by forming the mold case into a divided structure comprising a case body 2, a middle cover 3 with a recessed part partitioned by walls formed in the center part and a top cover 4 covering the upper surface of the middle cover, by storing contact parts, arc-extinguishing devices and an overcurrent tripping device in the body case and by storing the switching mechanism and a tripping mechanism in the recessed part of the middle case. Inter-electrode barrier ribs 2a and 3b for surrounding the contact parts and the arc-extinguishing device on an electrode basis to separate them from each other and partition-like mid-wall barrier ribs 3d for separating the contact parts of the respective electrodes, the overcurrent tripping device and a zero-phase current transformer from one another are formed between the body case and the middle cover of the mold case and thereafter a gas exhaust port 9c is opened in a back wall 9b of the arc-extinguishing device. COPYRIGHT: (C)2006,JPO&NCIPI |
