On the evaluation of low level contact erosion.

Abstract

The use of non contact laser measurement systems has introduced the ability to enable the precise measurement of volume change in relay contacts without the requirement of dismantling the main device. Following a previous study of volumetric erosion in DC automotive relays, an area of further investigation was highlighted. The further investigation deals with conditions leading to particularly low levels of erosion such as low current levels (5 A) and low operation lifetime (50-50000 cycles). The objective of the current study is to utilise recent improvements in resolution and measurement software of the system to perform a closer analysis of low level erosion contacts and determine the minimum level of erosion that can be detected. The study shows that current level is the defining factor influencing low level erosion samples. As the current level increases there is an enlarged erosion diameter. The study looks at the erosion processes and shows that current level has greater influence over contact erosion than the number of operation cycles.