| 摘要 |
PURPOSE:To enhance the reliability of a controller by using a self-overvoltage firing type of a photothyristor, and multiplexing a gate controller. CONSTITUTION:Many photothyristors 2' are connected in series, accessory circuits 3, 4 are provided to form a thyristor valve 1, and a photogate signal supplied from a gate controller is transmitted by a light guide 5' to thyristors 2' to control to be fired. The thyristor 2' is a self-overvoltage firing photothyristor having an overvoltage protecting function, and self-turned ON at overvoltage time. In this case, the light guide 5' has 2-branch type using LED terminals as 2-inputs to double a circuit in the gate controller. This dou bling is provided by providing the same circuits A, B of two systems and LEDs 7A, 7B connected in series are connected with the branching terminals of the guide 5'. thus, even if a defect occurs in the gate controller, the thyristor valve 1 can be controlled, and a defect system can be automatically disconnected and repaired. |
