RESEARCH ON SMALL CURRENT ARC EROSION OF SILVER/GRAPHITE CONTACT MATERIAL WITH LOW VOLTAGE AND RESISTIVE LOAD AT 400 Hz

Using a self-developed ASTM test system of contact material electrical properties of smallcapacity and the current-frequency changed,the performance comparison trials and material weighing of AgC,AgCdO,AgNi and AgW contact materials were completed under low voltage、resistive load and small current at 400 Hz and 50 Hz.The surface profiles and constituents of Ag-graphite contact material were observed and analyzed by SEM and EDAX.Researches indicated:the form of the contact material arc burnout at 400 Hz is stasis,not an eddy flow style at 50 Hz;meanwhile,the area of the contact burnout is less than that of 50 Hz,the ablation on the surface layer at 400 Hz is more serious.Comparing the capacities of arc erosion resistance of the silver-based alloy contact material with different second element at 400 Hz,it can be known that the capacity of the silver/graphite material is the weakest.