Ag接点の開離アーク消滅時ギャップ長と接点開離速度との関係に関する実験的検討

摘要

Ag接点の開離アーク消滅時ギャップ長に対する接点開離速度の影響を検討するために、直流誘導性負荷回路ならびに抵抗性負荷回路にて14V－0.1～2.0Aの電流を開離速度0.5mm/s、1mm/s、2mm/s、5mm/s、10mm/sで遮断し、アーク継続時間を測定した。その結果から平均アーク継続時間を算出し、その値と開離速度との積として平均アーク消滅時ギャップ長を求めた。誘導性負荷回路では、開離速度が大きくなるにしたがって平均アーク消滅時ギャップ長が長くなる傾向が認められ、負荷電流レベルが大きいほど、その傾向は顕著に観察された。抵抗性負荷回路の場合、平均アーク消滅時ギャップ長は数nm~数十nmのオーダであるが、開離速度が大きくなるにしたがって同様に長くなる傾向が観察された。%In order to study the influences of contact opening speeds on arc extinction gap length characteristics, Ag contacts were operated to break DC inductive and resistive load currents from 0.1 A to 2.0 A at 14 V with contact opening speeds of 0.5mm/s, 1 mm/s, 2 mm/s, 5 mm/s and 10 mm/s in a switching mechanism employing a stepping motor, and arc voltage waveforms were observed at each opening of the contacts. From the results, the average arc durations were determined at each current level under the respective contact opening speeds, and the average arc extinction gap lengths were calculated by multiplying the average arc duration value and the contact opening speed value. It was found that with increasing the contact opening speeds, arc extinction gaps became larger in the inductive load conditions. In the resistive load conditions, the similar tendencies were also observed, although the gap lengths were on the order of several tens ran or less.