FIELD: electric engineering. SUBSTANCE: device has subtractor, regulation unit, drive, electrode, current sensor, electrode movement speed sensor, first and second dividers and differentiating circuit. Output of current sensor is connected to first input of first divider through differentiating circuit. Output of electrode movement speed sensor is connected to second input of first divider, which output is connected to second input of second divider. Output of subtractor is connected to first input of second divider, which output is connected to input of regulator. Introduced elements provide possibility to send to input of regulation unit a signal which value is equal to value of error in regulation of arc length. This results in possibility to increase amplification gain of regulator and to take into account characteristics of drive. This results in increased precision of regulation. EFFECT: decreased time of melting. 2 dwg
