Powered testing of electrical contacts in mixed flowing gases

A series of industrial mixed flowing gas tests using real connectors were performed to investigate the effects of electrical power on the life of gold-plated contacts. The connectors were divided into three sets: unmated, unpowered, and powered. Change in contact resistance was used as the measure of contact performance. The results showed that with real contacts, the shielding provided by the housing, when a connector is mated, significantly inhibits corrosion at the interface, even in the harshest environments. As a consequence, levels of corrosion produced at the interface with the unpowered and powered sets were very small. A marginal increase in contact resistance was, however, detected when contacts had been powered to rated current. In order to investigate the phenomena in more detail, more severe atmospheres and less well-shielded connectors were used. These subsequent tests produced increases in corrosion at the contact interface, particularly for the powered sets. The change in resistance of the powered contacts was higher (sometimes greater than five times) than that of the unpowered sets. It is suggested that this result is due to the rise in temperature at the interface of the powered contacts increasing the rate of chemical reaction. Continuous monitoring of resistance during the tests produced resistance changes consistent with the phenomena of self-healing. >