| 摘要 |
The electrode (14) has an elongated first electrode element (22) which is arranged inside a second electrode element (26), forming an annular gas (24) through which gas flows. An arc is struck between said electrode elements in order to generate a plasma. The electrode (14) is arranged parallel to the direction of the magnetic flux, which results in the arc rotating about the first electrode element (22). In order to increase the power and/or to suppress erosion, the electrode material, current density and gas pressure are selected such that a cathode spot occurs, the first electrode (22) having a uniform cross-section along its operating section. This longitudinal movement is superimposed on the rotation and can be further intensified in various ways. In this way, the arc of an electrode can move much more intensively within a cavity which is located along one or more openings in the electrode. This results in the ionised gas filling the entire cavity and being forced into the generator duct, where it acts as a gas electrode. At the same time, erosion is in this way suppressed so that it is possible to operate with higher current densities than in the past. The high temperature of the electrode prevents carbon slag being deposited on the electrode opening so that a path which is electrically conductive to a large extent remains open for the load current. <IMAGE> |
