| 摘要 |
PURPOSE:To employ only one optical cable for transmitting a defect monitor signal from a high voltage side to a low voltage side by using the signals of a plurality of thyristors connected in series as information of pulse width. CONSTITUTION:The voltages of two continuous thyristors 1, 2 of thyristors 1, 2... connected in series are simultaneously monitored by a voltage detector 51 between an anode and a cathode. The output of the detector 51 is transmitted through a logic calculator 52 and a pulse width regulator 53 to a light emitting unit 54, and different light pulse signals are generated in response to the detected content of the detector 51 when one of the thyristors is defective, when both are defective and when both are normal. The light pulse signal is transmitted through one optical cable 56 to a low voltage side, and transmitted from a photoreceptor 57 through a pulse width detector 58 to a controller 59. |
