In order to study the influences of contact opening speeds on arc extinction gap length characteristics, Ag contacts were operated to break DC inductive load currents from 0.1 A to 2.0 A at 14 V with contact opening speeds of 0.5 mm/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 average arc durations showed no significant differences with increasing contact opening speeds. Thus, arc extinction gaps became larger at faster opening speeds in the inductive load conditions of this study.

The purpose of this study is to examine the impact of the opening speed on a breaking arc. The opening speeds are 10, 20 and 30 mm/s. The breaking arc is generated in a D.C. 42 V/10.5 A circuit, and the arc voltage, the arc current, the gap length and the arc spectrum intensity are measured. Arc temperature is calculated by using a Boltzmann plot. Even if the opening speed is changed, the arc temperature starts from a high temperature, and falls gradually to 4650-4750 K with time. Namely, the opening speed has no influence on the arc temperature.

Ring head recording on single-layer perpendicular recording media was studied by a simple simulation analysis based on a loop tracing method considering only the perpendicular component. Although the assumed model was primitive, the simulation results qualitatively well explained the experimental results such as a decrease in output at high recording currents and its relaxation upon using a smaller gap-length head. The simulation results revealed that achievable recorded magnetization is, in general, much smaller than the saturation value due to a broad distribution of the ring head field, but a medium with a steeper slope in the perpendicular M-H loop could improve the recording performance. This was confirmed experimentally for the medium with a steeper loop slope, though the medium exhibited a larger medium noise at high densities. It was suggested that the development of perpendicular recording for higher output and lower noise could be performed for both media with a small and steep loop slope. The former should be improved by means of the recording head while the latter by the media. A large improvement is expected for both cases.