| 摘要 |
<p>The plasma torch (10; 11, 12, 14) comprises an electrical supply (20) with an arc circuit (21) and a coil circuit (22) which are mounted in series and with means (30) for controlling the strength of the current flowing through the coil (22) and consisting, among other things, branched off from this coil (14), of a chopper composed of a battery of capacitors (31) and of at least one electronic power switch (32) which can be placed far from the coil. The electronic switch is preferably of the thyristor-diode type (321, 322) with resonant de-energising circuit (31, 323). A variant of this chopper uses at least one electronic switch of the GTO thyristor type with controlled triggering and controlled turn-off, or at least one conventional thyristor equipped with an auxiliary extinction circuit. Application to torches of high power for industrial use, for example metallurgical. <IMAGE></p> |
