Degradation phenomena of electrical contacts using hammering oscillating mechanism and micro-sliding mechanism — Oscillating amplitude, natural frequency and damping ratio caused by the mechanisms

Authors have studied the influence on contact resistance by actual micro-oscillation to electrical contacts using some oscillating mechanisms in the vertical direction. First, the authors discussed the difference of time-sequential fluctuations in the contact resistance when contact frictional force between male-pins and female-pins were “usual”, “smaller” or their “middle”, using hammering oscillating mechanism (HOM). It was shown that the contact resistance was increasing and fluctuating under the “middle” friction. Second, they showed that there was a degradation phenomenon of electrical contacts by experimental results using the micro-sliding mechanism (MSM). Using the results the authors discussed the degradation phenomena in shorter term, about a day, on four types of conditions that the input waveform as external force was sinusoidal or rectangular and frictional force between male-pins and female-pins in a connector was “usual” or “smaller”. Consequently it was shown that there were (1) the minimal sliding amplitudes causing contact resistance fluctuations of electrical contacts and (2) the amplitudes correlating input waveforms and contact frictional forces. In comparison to micro-sliding mechanism (MSM), it was indicated that the difference of the contact frictional force was related to degradation phenomenon of electrical contacts and there was critical relative displacement or the region between male-pins and female-pins by oscillations using hammering oscillating mechanism (HOM) with 150G. However the authors recognized that the amplitudes were not strictly equal to the relative displacements between male-pins and female-pins. It is important for them to measure or observe the relative displacements by way of a newer instr