plastic case circuit breaker, also known as device circuit breaker, all the internal parts are enclosed in a plastic case, the internal components are modular, with strong sectional ability and isolation protection ability. next, we will introduce the main functions and functions of the plastic case circuit breaker. the functions of
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1 and
circuit breaker's sectionalization ability has two indexes: rated limit breaking ability and rated short circuit sectionalization ability (ics). as a characteristic parameter, ics not only considers the sectional capability of circuit breaker, but also acts as an index, that is, it can work normally after several short circuit currents are cut off. molded case circuit breaker should have enough icu and function of breaking circuit breaker. according to the regulations, the ics of the plastic case circuit breaker is qualified as long as it is more than 25% icu. therefore, only icu is considered for distribution systems with low power supply requirements.
2 and current limiting interruption ability
refer to the ability of limiting fault current when circuit breaker short circuit trips. when the circuit breaker is short-circuited, the rapid opening of contacts produces arc, which is equivalent to a rapidly increasing arc resistance in series in the circuit, which limits the increase of fault current. the shorter the breaking time of circuit breaker, the closer ics is to icu, the better the current limiting effect, which can greatly reduce the adverse effects of short circuit current on electrical equipment and prolong the service life of circuit breaker. the role of