| 摘要 |
PURPOSE:To reduce the demand of switching loss by detecting a surge by the discharge currents of an arrester connected in parallel with a thyristor arm and inhibiting ignition signals to the thyristor bulb. CONSTITUTION:The arm arrester 7 connected in parallel with a thyristor element row 21 discharges electricity when the external thunder surge, etc. are applied, the discharge is detected by an arrester discharge current detecting circuit 27, and the ignition signals S1 forwarded to an ignition circuit 30 are blocked by the detecting output. Accordingly, the ignition circuit 30 does not give the ignition signals to a thyristor element 22 even when the ignition signals S1 reach. |
