Experimental Study of the Vibration-Induced Fretting of Silver-Plated High Power Automotive Connectors

Relatively little is known about the fretting mechanism of high power connectors used in hybrid vehicles, even though the vehicles are widely being introduced to the market. This work experimentally investigates the fretting mechanisms of silver-plated high power connectors caused by vibrations. In order to emulate operational and environmental effects, a test stand was designed that is capable of measuring ECR, relative displacement and connector temperature. The experimental results show that the variation of electrical contact resistance (ECR) of connectors subject to vibration is primarily due to periodic changes of contact area caused by relative motion between the contact interfaces, rather than other fretting corrosions. This finding is reinforced by observing a good correlation between relative motion and the increase of ECR under vibration. When a vibration stopped, the ECR decreased to a value that is slightly larger than the original value. A surface analysis showed no obvious corrosion until the coating was worn away.