抄録
Experimental investigation on short-circuit phenomenon through ejected hot gas between source-side terminals in molded case circuit breakers (MCCB's) was performed. The occurrence rate of short-circuit phenomenon proved to increase with the peak value of breaking current and with the order of breaking test. The conductance of the ejected hot gas was also found to rise with the peak value of the breaking current and with the order of the breaking test. These results indicate that the hot gas with high conductance causes the short-circuit phenomenon to happen. Then some effective means were taken in the MCCB to reduce the conductance of the hot gas. Decreasing in the conductance of the hot gas successfully prevented the short-circuit phenomenon from occurring.
