Correlation of surface contamination introduced by feeding equipment on electrical contact resistance

Contact degradation caused by austenitic stainless steel feeder bowls has raised concern among manufacturers of electrical contacts. The surface contamination of three contact materials, fine silver, silver cadmium oxide (90%Ag 10%CdO), and a silver alloy (75%Ag 24.5%Cu 0. 5%Ni) with 15-microinch (Ra) surface finish, was investigated. Contact resistance probing was employed and surfaces were analyzed to explain the degradation process. The investigation elucidated the effects of various vibratory feeder bowl coatings which reduced surface contamination. The attainment of low contact resistance was explained as interactions among nobility of contact material, type of coating, and time spent in the vibratory feeder bowl.<
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