The effect of erosion and contact resistance of electrical contacts in n-hexane on contact reliability

The purpose of this work is to make clear the phenomena of electrical contacts in liquid environments with light-duty application. The automotive electronic fuel pump is operated by a small D.C. motor and its commutation arc is carried out in gasoline. A commutation arc can be regarded as a kind of breaking arc. Therefore we projected the application of a commutation arc in gasoline to electrical contacts. The break operation studies have been conducted on Ag and Pd materials under the inductive condition in three different dielectric liquids (distilled water, methanol and n-hexane). The characteristics of the contact resistance and material transfer are strongly affected by dielectric liquids. According to our research, judging from material wear and contact resistance, there is the possibility that better contact reliability can be attained in n-hexane with a low load current. This is because in n-hexane there is very little wear and flat erosion can be achieved, due to the film on the contact surface made of carbon that is contained in n-hexane. But the contact resistance occasionally becomes high and unstable with a high load current. Thus, this paper mainly reports the results of the detailed experiment about erosion and contact resistance in n-hexane.