光切断法を利用した接点表面形状の計測システムに関する実験的検討（2）

摘要

Contact surfaces of mechanical relays and switches are often damaged by arc discharges and/or mechanical wear during switching operations. Conventionally, erosion and transfer characteristics of various contact materials under different load conditions have been mainly studied based on observation and evaluation of contact surfaces after switching operation tests. On the other hand, a further detailed study will become possible if we can observe and numerically evaluate a changing process of surface damages (especially, growth of a crater and/or a pip) on contact surfaces during switching operations. For that purpose, a numerical evaluation system of contact surface damages by way of an optical cross-section method is being constructed. In this paper, Ag contacts were operated to break a DC inductive 14V-1A or 2A load current for 50,000 operations. During the switching operations, the movable contact (cathode) surface profile (a crater growth process) was numerically evaluated with the optical cross-section method, and further, the counterpart fixed contact (anode) surface profile (a pip growth process) was also observed with an additional camera system.%メカニカルリレー・スイッチの電極表面は、開閉動作時のアーク放電や機械的磨耗により損傷を受ける。一般に開閉動作終了後に電極表面形状を観察・評価するが、開閉動作中に電極表面形状の変化（クレータや突起の成長過程）を経時的に観察・評価できれば、より詳細な比較検討が可能になる。そこで、動作中の観察の実現を目指して、光切断法を用いた電極表面形状の評価システムの構築を進めている。今回は、直流誘導性負荷回路で14V-1A又は2Aを遮断するAg接点対に関して、これまでに実現した固定側電極（陰極）表面のクレータ形状の観察に加えて、対向する可動側電極（陰極）表面の転移突起の成長過程の観察も試みた。