DEVICE FOR CONTROL OVER ELECTRIC MODE OF THREE-PHASE ELECTRIC ARC FURNACE Russian patent published in 1995 - IPC

FIELD: electrical engineering. SUBSTANCE: device includes three subtracters, three regulators, three drives, three electrodes, three differentiators, one adder and three regulators of insensibility zone. Outputs of current pickups are connected through corresponding electrodes to inputs of adder which output is coupled to controlling inputs of regulators of insensibility zone. Output of subtracter is linked to input of regulator of insensibility zone of corresponding phase. Outputs of regulators of insensibility zone are connected to proper inputs of regulators of drive. These elements make it possible to sum up present values of derivatives of controlled parameter of three phases and those of their mutual compensation caused by interaction of three phases. In those cases when changes of controlled output parameter are mot intercompensated output signal of adder different from zero diminishes insensibility zone of regulator. EFFECT: enhanced operational efficiency thanks to increased precision of control. 1 dwg