Design, delivery and adjustment of electric equipment for screwdown structure drive of mill «1500».
The works on replacement of obsolete and worn-out thyristor converter and exciter for screwdown structure motors by a new digital DC converter of Sinamics DCM series with a built-in exciter were finished. The redundant motor supply circuit operating from variable-voltage system was left as it is.
Besides, process control system of screwdown structure was integrated into existing process control system based on PLCs and workstations that were installed and put into service by «ASC» company in 2015. The distinguishing feature of automatic control system of screwdown structure is that the field decay mode is applied at speeds exceeding the rated value without the use of speed sensor.
Besides, due to use of common armature converter for both adjusting screws the automatic control system implements the function of parameter adaptation to the currently controlled unit (only left screw in operation, only right screw in operation, joint action). Availability of redundant supply from variable-voltage system allowed to minimise mill service interruption for the time of execution of electrical installation and commissioning works. Mill service interruption lasted for 5 days.