| 摘要 |
PROBLEM TO BE SOLVED: To suppress the wear of electrodes, to execute efficient heating and to continuously produce graphite powder by providing a furnace casing with three pairs of the electrodes for each of respective phases of a three-phase AC power source arranged to face this furnace casing and executing electrical heating by switching the respective phases in such a manner that a non-conducting state is attained only for the period of a prescribed angle. SOLUTION: The electrodes arranged to face the carbon powder packed in the furnace casing 1 so as to hold the carbon powder are energized to heat and graphitize the carbon powder. The electric power of the respective phases supplied to a voltage transforming means 12 under driving by a controller 13 for each of the respective phases R, S, T of the three-phase AC power source 10 is switched by a switching means 11, is subjected to voltage transformation by the voltage transforming means 12 and is supplied to three pairs of the electrodes 8R1, 8R2; 8S1, 8S2; 8T1, 8T2. The respective phases R, S, T of the three-phase AC power source 10 are switched so as to be made non-conducting only for the period of the prescribed phase angle, preferably the phase angle of >=60 deg. from the zero cross points of the respective phases by the switching means 11 and are impressed to the electrodes. |
