To provide a method and device for preventing damage to a furnace by detecting a power current or a leakage current in the abnormal condition of a plasma melting furnace, determining the abnormality thereof and controlling power voltage appropriately.
The power supply control method for the plasma melting furnace comprises using a DC power supply for applying voltage between a main electrode and a bottom electrode opposed to each other and inserted into a furnace body to generate a plasma arc and using the plasma arc for giving melting treatment to materials to be melted. The leakage current flowing between the main electrode side furnace body and the bottom electrode side furnace body electrically insulated from each other by an insulating material is measured, the DC power supply is cut off immediately when the leakage current is about 200A or greater, the DC power supply is cut off after the passage of a preset time when it is about 50A or greater and smaller than 200A, the charge of the materials to be melted into the furnace is stopped after the passage of a preset time when it is about 20A or greater and smaller than 50A, and an alarm is only output and the operation is kept on when it is smaller than about 20A, thereby preventing damage to the furnace resulting from the leakage current.
COPYRIGHT: (C)2005,JPO&NCIPI
Tomohiro Harada
Keita Inoue
Shuzo Miura
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