METHOD FOR DETECTING PRECURSOR OF GENERATION OF ARC DISCHARGE FOR GLOW DISCHARGE TREATMENT, METHOD FOR PREDETECTING, SUPPRESSING ARC DISCHARGE FOR GLOW DISCHARGE TREATMENT AND GLOW DISCHARGE TREATING DEVICE

摘要

PROBLEM TO BE SOLVED: To surely detect the precursor of arc discharge in an early stage from the degree of the unbalance of the discharge currents by detecting the discharge currents to a treating vessel, inputting the same into a sample hold circuit and comparing the discharge currents each ignition cycle in an inverter circuit. ;SOLUTION: Commercial three phase alternating currents are applied to the main circuit 2 via a rectifying circuit 3 and a smoothing circuit 4, pulse-shaped discharge voltage generated in an inverter circuit 5, a step-up transformer 6 and a rectifier 7 is applied to a treating vessel 8 to generate glow discharge, and the object S to be treated in the vessel is subjected to nitriding treatment or the like. At this time, the discharge current on the primary side or the secondary side in the step-up transformer 6 is detected by a current transformer 17 for detecting the currents and is inputted into a sample hold circuit 20 together with a control unit 18. Each ignition cycle in the inverter circuit 5, on every prescribed minute time, the discharge current is sample-held, and moreover, the corresponding discharge currents in each cycle are compared, and from the degree of the unbalance between both discharge currents, the precursor of arc discharge is detected.;COPYRIGHT: (C)1999,JPO