| 摘要 |
PURPOSE:To prevent occurrence of a short-circuit trouble and the like by the simultaneous ignition of a thyristor in forward and backward directions even when a service interruption occurs at any time by a method wherein the difference between the detected information of voltage drop and the forward and backward directions of current circulating at the detection timing is recorded, and after the voltage has been recovered, the initial control of the thyristor is conducted in accordance with the above-mentioned record information. CONSTITUTION:In a DC power supply method for induction load using a thyristor provided with forward-backward switching function, the drop to the prescribed value or lower of the DC voltage supplied to a control device for the DC power supply method is detected, the information of the above-mentioned detection and the distinction of the forward and backward directions of the current circulating at the timing of the above-mentioned detection are recorded, and the initial control of the thyristor is conducted in accordance with the above-mentioned information of record after the restration of control device feeding DC voltage. For example, when the control device feeding DC voltage drops and the prescribed condition is obtained, a service interruption flag is erected on the service interruption recording resistor provided on the control device and 1 is recorded. Also, when the control command signal at the above timing is in forward excitation, the forward-backward recording resistor, provided on the control device, is made zero in value and 1 is recorded in the case of backward excitation. |
