A Study of Contact Spots on Earthquake Disaster Prevention Relays(Session 4 -Relays-)

概要

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This paper reports on the effect of switching action on the contact surfaces of earthquake disaster prevention relays. Large-scale earthquakes occur frequently in Japan bringing with them extensive damage, and fire caused by electrical equipment is one example of the serious damage which can occur. Earthquake sensors capable of maintaining a high level of reliability when earthquakes occur play an important role as a means of minimizing this damage. To this end, we carried out observations focusing on samples which had either been subjected to an electric current of 10mA or 0.1A. The 10mA samples exhibited low, constant contact resistance despite the addition of seismic motion, while the 0.1A samples exhibited varying contact resistance values and damage on their contact spots resulting from the addition of seismic motion. The sample surfaces were then viewed using an atomic force microscope (AFM) in tapping mode and a surface potential microscope (SPoM). As a result, we discovered that even the unused earthquake disaster prevention relay (standard sample) which had a surface lined with asperities on its parallel striations developed irregular protrusions due to dust and other deposits. In addition, scanning the contact surface with the SPoM at the same potential revealed the occurrence of differences in surface potential which varied in response to the asperities on the striations.
社団法人電子情報通信学会の論文
2007-11-07