| 摘要 |
PURPOSE:To obtain an arcless and compact thyristor switch for DC use by using the relay driver circuit using the auxiliary relay to charge the capacitor of the commutation circuit. CONSTITUTION:With closure of making signal contact 3, the ignition signal is given to the gate of thyristor 6 to secure conduction. And the DC current flows to making coil 2, and breaker 11 is made. Then, the voltage division is given to the load current signal detected by resistor 8-10 via viriable resistor 8-1 and the operation of off-signal generator circuit 8, thus the off-signal generation current level being controlled. This signal turns on transistor 8-7 when it is over the fixed level to actuate relay 8-8. As a result, the charge of non-polarized electrolytic capacitor 10-3 and 10-4 are discharged in the same direction and in piling to supply the reverse current to thyristor 6. Thus, the zero point of the current is set forcedly to turn off thyristor 6. |
