| 摘要 |
The plasma torch (10; 11, 12, 14) comprises an electrical power supply (20) with an arc circuit (21) and a coil circuit (22) which are mounted in series and with means (30) for controlling the level of the current flowing in the coil (22) consisting, inter alia, mounted in parallel with this coil (14), of a chopper consisting of a battery of capacitors (31) and of at least one electronic power switch (32) which may be placed distant from the coil. The electronic switch is preferably of the thyristor diode (321, 322) type, with a resonant turn-off circuit (31, 323). A variant of this chopper uses at least one electronic switch of the GTO thyristor type, controllable in triggering and in switching off, or at least one conventional thyristor equipped with an auxiliary extinction circuit. Application to high-power torches, for industrial, for example metallurgical, use.
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