| 摘要 |
PROBLEM TO BE SOLVED: To accurately operate an annunciating circuit for elimination of hysteresis, by comparing a DC voltage output value with reference voltage for averaging, and annunciating its output signal. SOLUTION: A load factor display device consists of an absolute value circuit 6 which full-wave-rectifies AC voltage outputted from a current detector 5 for detecting electric current of the voltage wire of a single-phase three-wire system cable line on the primary side of a main line breaker 2 and outputting AC voltage, a voltage comparison circuit 8 which compares, with reference voltage, DC voltage outputted from the first average circuit 7 for outputting DC voltage whose full-wave-rectified waveform outputted from the absolute value circuit 6 is averaged, and an annunciating circuit 10 which annunciates a signal outputted from the second average circuit 9 for averaging a signal outputted from the voltage comparison circuit 8. As a result, the inputted voltage of the voltage comparison circuit 8 in this load factor display device 1 is changed gradually linearly, and the second average circuit 9 conducts averaging even if a pulse waveform is outputted when the voltage almost exceeds the reference voltage, thus operating the annunciating circuit accurately. |
