| 摘要 |
In a circuit breaker (3) having a thermal-magnetic trip (17), the voltage across the bimetal (19) is used to sense load currents. This voltage signal representative of current through the bimetal (19) can be used as an input to an arcing fault detector (25). The signal is converted to a bandwidth limited di/dt signal. If the magnitude of the di/dt signal exceeds a threshold indicative of the onset of an arc a predetermined number of times within a given interval, the circuit breaker (3) is tripped. The voltage across the bimetal (19) can also be used in other devices requiring a measure of load current such as, for example, a meter (99) or an overcurrent alarm (103). <IMAGE> |
