| 摘要 |
PURPOSE:To prevent the occurrence of a quenching phenomenon which is caused by a sudden change of coil current and to produce a high voltage at a plasma circuit, by connecting a capacitor for time constant control or a resistance in parallel to a current transformer coil. CONSTITUTION:A power supply 13 is shifted to the operation of an inverter, and a main thyristor 8 of a thyristor breaker 7 is ignited. Thus the current of a current transformer coil 1 flows to the thyristor 8. When an auxiliary thyristor 9 of the breaker 7 is ignited, a commutating capacitor which is previously charged is discharged. And the commutating current breaks the current of the thyristor 8. The commutating current flows to a capacitor 30 of the low impedance, and the voltage between the current transformer coil terminals increases to induce the voltage at a plasma circuit 2. A switch 31 for application is ignited by a plasma ignition detector 34 and through a controller 37. Thus the current of the coil 1 flows to a time constant controlling resistance 6. |
