Design Of Testing Device And Research On Sliding Electrode Erosion Under High Current

In the thesis, a testing device was designed to research the erosion of slidingelectrode under the high currents, which has self-owned intellectual property. This devicehas many characteristics, such as small, assembly easy, the comfortable to adjust contactpressure and current, etc.. There were three types of electrodes were evaluated purealuminum electrode, aluminum alloy electrode and aluminum alloy electrode platedindium (indium coating, about50μm, plated to the surface of electrode by brush plating).The stationary electrode was pure Cu.The test current and contact pressure were in therange of110~150kA and0.25~2.0kN, respectively. The experimental voltage and currentwere recorded by oscilloscope, the Rogowski coil and high-voltage probes.The results show that the weight loss of sliding electrodes increased as currentincreases&contact pressure reduces. It seemd that the contact pressure had the greatinfluence on reducing the erosion of sliding electrode. Suitable contact pressure washelpful for reducing erosion of sliding electrode. The aluminum alloy electrode platedwith indium demonstrates the minimum loss of mass caused by erosion, about0.50~0.8g.The pure aluminum showed the maximal mass loss, compared with that of aluminumplated indium and aluminum alloy electrodes. The typical erosion layer of slidingelectrode was observed after the experiment under high current. It was observed that theerosion surface of aluminum alloy with indium was the smoothest than that of aluminumalloy and pure aluminum eletrodes. SEM and EDS analyses showed that, the erosion layerwas covered by molten and unmolten metal particles, which contained pore with differentshapes and sizes.Cracks were only found on the erosion layer of aluminum alloy electrodes. Thetransfer of copper was not found in aluminum alloy electrodes and aluminum alloyelectrodes plated with indium, but it was found easily on the erosion surface of purealuminum sliding electrod.Erosions degree of stationary electrodes were different with the changes of slidingelectrode materials. Stationary electrodes with pure aluminum sliding electrode may cause the severely damage during the high current test. In contrast to the above test, noobviously severe damage was observed on the sliding contact surface of aluminum alloyand electrode plated with indium. Indium-plated layer could reduce the contact resistanceand coefficient of friction.