| 摘要 |
A circuit breaker having the overcurrent tripping characteristic, which is capable of detecting an overcurrent flowing through the main circuit between an AC source (1) and a load (2). The circuit breaker comprises a pre-alarm circuit (20) having a pre-alarm characteristic, a pre-alarm signal output circuit (21) for producing an alarm in response to the output of the pre-alarm circuit (20) and a photocoupler (27) for controlling the data transmission between the circuits. The circuit breaker can detect the main circuit current before it becomes an overcurrent and generate the alarm accurately. |
