ANORDNING FOR SKYDD AV PLASMATRONER MED HOG EFFEKT

摘要

To prevent nozzle destruction in a high-power plasmatron such as is used in plasma melting furnaces photodetectors (5) are provided which can recognize heavy-current subsidiary arcs and supply control signals to a protective control circuit. The photodetectors (5) are disposed in the gap (6) between the cathode (3) and the nozzle (4), behind the nozzle outlet aperture so that they overlook adjoining zones of the outlet aperture.