Experimental Determination of Most Suitable PID Parameters for ARC Gap Control Loop in Vacuum Arc Re-melting Furnace

This paper deals with a closed loop position control of a consumable electrode in Vacuum arc re-melting furnace, essential for maintaining the arc in high current melting process. In order to maintain arc (required to melt the electrode) between electrode and molten pool throughout the melting process in the evacuated chamber, position and thereby arc gap needs to be precisely controlled. A servo motor with integrated differential gear box coupled with a threaded screw mechanism is employed for regulating the position of the electrode. In this paper, a study is carried out to determine optimal PID parameters required for stable servo motor operation without compromising necessary dynamic response of the system. Characteristics of each parameter in a PID loop and their effect on the system response is also discussed in this paper along with finalized parameters and resultant response.