| 摘要 |
<p>PURPOSE:To suitably prevent the breaking of an electrode at an initial stage of melting as well as the overload of an apparatus, and to stably retain discharge power after an intermediate stage of melting by automatically varying the sensitivity of elevation control of the electrode, with regard to the melting progress detected by a melting progress detection means. CONSTITUTION:When an installed material is melted by an arc, and the arc is elongated thereby, since discharge current is reduced while discharge voltage is increased, an output signal SD of a differential amplifier 30 becomes negative, and a signal for descending an electrode 16, is output from a driving circuit 34. On the contrary, when the arc is shortened due to the electrode 16 being lowered and so on, since discharge current is increased while discharge voltage is reduced, the output signal SD of the differential amplifier 30 becomes positive, and a signal for elevating the electrode 16 is output from the driving circuit 34. The elevation of the electrode 16 is automatically controlled through the operation of an elevation control circuit 28, so as to define the stable length of the arc, and dissolving power reaches a predetermined stable level.</p> |
