| 摘要 |
<p>1. Anti-extinction device for the arc in a plasma torch (1) with a negative voltage/current characteristic, making it possible momentarily to modify the current and voltage operating point of the said arc by acting as a function of the arc voltage on the current reference applied to a loop for controlling the current of the said arc, characterized in that it comprises a threshold detector (15) emitting a signal intended to increase immediately the intensity of the reference current applied to the said loop from the moment when the said arc voltage is higher than a specific value and, in series with the said threshold detector (15), an amplifier (16), the gain of which falls progressively as a function of the time elapsed since the emission of the said signal, so as progressively to attenuate the latter and gradually return the intensity of the reference current to its nominal value.</p> |
