| 摘要 |
PURPOSE:To stably conduct a forward-backward switching operation, and to cut down the cost by removing useless resistors by a method wherein the power supplied from a forward thyristor is stopped, and after the lapse of prescribed time from the time when the supply voltage to load has been dropped to the prescribed voltage value, the supply of voltage from the backward thyristor is started. CONSTITUTION:In the power supply method of inductance load using a thyristor provided with forward-backward switching function, first, forward-backward switching is conducted when the power supply is forward-backward switched, and the power supply from a forward thyristor is stopped. Then, after lapse of prescribed time from the point where the supply voltage to the load dropped to the prescribed voltage value (beta), the power supply from a backward thyristor is started. For example, a forward excitation cut treatment is started at the timing (t1), and when the voltage (v) becomes lower than the prescribed (beta) at the timing (t2), the output of a gate trigger pulse against the thyristor on the forward excitation side is stopped, and at the same time, a timer is set, a striking pulse against the gate of the thyristor on the backward excitation side is set at the timing (t2), and backward excitation is set. |
