| 摘要 |
PURPOSE: An electronic mold case circuit breaker is provided to improve user convenience by permitting the trip unit of the circuit breaker to have an auxiliary signal function and eliminating the need of arranging an auxiliary signal contact. CONSTITUTION: An electronic mold case circuit breaker comprises R-phase, S-phase, and T-phase current transformers; a rectifying unit(24) for full wave rectifying the signals output from the transformers; an amplifying unit(25) for amplifying the signals output from the rectifying unit; an instantaneous detection unit(27) for receiving current from the amplifying unit and detecting over current; an A/D converting unit(28) for converting the analog signal received from the amplifying unit into a digital signal; a characteristic set unit(29) for setting characteristics desired by a user; a micro processor(31); an auxiliary signal contact display unit(32); and a trip unit(34). The micro processor compares the digital value received from the A/D converting unit and the digital value set by the characteristic set unit, generates a trip signal upon occurrence of over load, detects output signals of the transformers, and generates operation indicating signals for indicating on/off operation of the electronic mold case circuit breaker. The auxiliary signal contact display unit receives the operation indicating signals from the micro processor, and displays on/off operation of the electronic mold case circuit breaker. The trip unit carries out trip operation by one of the signal outputs from the instantaneous detection unit and the trip signal received from the micro processor.
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