| 摘要 |
<p>PURPOSE:To increase safety and reliability of operation by providing a variable voltage and variable frequency inverter control device to reduce the generation of a voltage flicker and at the sane time to supply the three-phase alternating current of the most suitable frequency for the inside state of a furnace. CONSTITUTION:A variable voltage and variable frequency (VVVF) control device 8 selectively controls the frequency of a three-phase alternating current to be supplied to a three-phase alternating current arc furnace (AC furnace) so as to be the most suitable frequency in accordance with the inside state of the furnace at the initial melting period of a material, the main melting period, the final melting period, the refining period and the like. Thereby, the operation of high efficiency of the AC furnace 1 can be achieved. Also, in the case where a fluctuating current to exceed the set-up current of the AC furnace 1 is generated due to the irregular approach and contiguity between a melted and refined material and a three-phase graphite electrode 2, an electrode control device 7 controls a current and at the same time the VVVF inverter control device 7 instantaneously controls a voltage supplied to the arc furnace to control the current of the AC furnace to a set-up value, thereby reducing the generation of a voltage flicker.</p> |
