The Influence of the Bonding Area of welded Contact Tips on Contact Erosion

The influence of both the size and location of the bonding area of resistance-welded contact tips made of Ag/SnO₂ 86/14 on contact erosion was examined on an 11-kW AC contactor. AC4 utilization category at 110 A was used to perform the service life tests. It could be shown that the medium erosion rate was only slightly increased with bonding areas of down to 30%. The 90% erosion rate value, however, significantly rose with the decrease of the bonding area. Bonding areas of 30 and 40% resulted in partial early failure by the detachment of the contact tip. No remarkable influence of the bonding area to erosion values related to the arc moving direction could be determined. It was proven that the overtemperature value was evidently no function of the bonding area under the conditions specified in these tests.