Effect Of Materials And Structure In Sliding Electrical Contact Under High Current

There was the uneven distribution phenomenon of current on the conductor crosssection, the high current density always located on the conductor surface and the weakcurrent density located inside in the process of sliding electrical contact. The skin effectmade the contact surface overheat on the part of sliding electrode, which causedelectrical erosion. At the same time, the concentrated heat could make the electrode wearand crack in the contact position, which caused arcing. These would affect the servicelife of the electrode, the reliability and stability during the sliding electrical contactsystem.By the fiber brush, the experiments to disperse current effectively and smooth awaythe problem on the concentration of current density were studied in this paper. The effectof different diameter (0.1mm or0.2mm) of aluminum alloy brush and the copperbrush sliding electrode were carried out during the sliding electrical contact under highpulse currents. The fiber brush could meet the conditions of the high current density well,low resistance and some strict requirements such.The result revealed that: the structure of the brush sliding electrode appeared higherstrength during the experiment and kept in good condition, which indicated that thestructural design of sliding electrode could be fit for the requirements to strength and thebrush sliding electrode of aluminum alloy. All of these were still applied to the pulsedmagnetic field in the high current intensity, when the current was increased to350kA.During the sliding electrical contact, because the plastic and wear resistance of thealuminum alloy were better than copper, the performance of sliding electrode ofaluminum alloy was better than that of copper. The fiber materials of sliding electrodehad certain damage, including porosity and metal molten on the contact surface. Thecolumnar crystals grew in the ablation layer of the electrode, which reduced the useperformance of the materials. In addition, because the relatively thick electrode materialhas better wear resistance and strength, the properties of Φ0.2mm brush sliding electrode were better than that of Φ0.1mm. The optimal contact pressure was about2.0kN in theexperiment. When the current achieved to250kA, it caused serious damage to thematerials of electrode.During the sliding electrical contact, the relatively thick and high plastic strength ofaluminum alloy metal fiber showed the proper contact pressure and better performance.