| 摘要 |
An alarm circuit is provided which takes the place of auxiliary contacts that are generally used in association with circuit breakers or fuses to provide an alarm warning in the event that the circuit breaker or fuse in series with a load has opened for any reason. The alarm circuit is provided with a high resistance resistor that is connected to the load end of the circuit breaker, and at the other end of the resistor to a high gain amplifier or solid state switch. The output of the high gain amplifier is connected to a remote signal relay, which may be DC relay or an AC relay. The arrangement is such that the high gain amplifier becomes conductive in the event that the circuit breaker opens, thereby causing an alarm indication. Indicators are associated with the circuits, including an LED to provide a local signal indicative of the fact that the relay has changed its state. A remote alarm circuit is driven by the change of state of the remote signal delay. Because the alarm circuit monitors the circuit breaker itself, a true indication of the fact that the circuit breaker has opened is assured.
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