| 摘要 |
An improved current-limiting section is provided for an interrupting device. A main-current-path section of the interrupting device carries substantially all of the normal, load current while only a negligible portion of the current flows through a higher-impedance current-limiting section. Upon operation of the interrupting device, the contacts of a switch in the main-current section are rapidly separated to create one or more gaps. Upon the creation of the one or more gaps, the current is transferred into the current-limiting section. The current-limiting section includes a plurality of fusible elements. The fusible elements are thin, elongated, conductive ribbons. One or more of the fusible elements has a first predetermined pattern of reduced cross-sectional areas that is different than a second predetermined pattern of reduced cross-sectional areas provided in the one or more remaining fusible elements such that for low overcurrent conditions, the one or more fusible elements having the second predetermined pattern melt and have gaps created therein at an earlier time than the one or more fusible elements having the first predetermined patterns. At high overcurrent conditions, the melting characteristics of the fusible elements having the first predetermined pattern and the melting characteristics of the fusible elements having the second predetermined pattern are substantially equal.
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