| 摘要 |
A circuit breaker includes for each neutral and phase power conductor, a current sensor sensing an alternating current flowing in a corresponding power conductor, a comparator determining whether the sensed alternating current is positive or negative, a rectifier rectifying the sensed alternating current to provide a rectified current value, and an analog-to-digital converter converting the rectified current value to a signed digital value having a positive sign. A processor cooperates with the comparators and the analog-to-digital converters and includes a routine that changes the positive sign of the signed digital value to a negative sign if the sensed alternating current is negative, adds the signed digital value for each power conductor to provide a sum, and employs the sum to determine whether to output a ground fault signal. The processor further cooperates with an operating mechanism to trip open separable contacts responsive to the ground fault signal.
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