Experiment and simulation analysis of surface structure for CuW contact after arc erosion

Abstract

As an electrical contact, CuW alloy tends to be eroded under high voltage arc, and cracks would appear on the surface of the contact. Arc erosion experiments under high voltage arc were implemented on CuW contact, and then the inner stresses were analysed with the finite element method. Results showed that the surface of the CuW contact was changed to graded structure, including tungsten, tungsten skeleton and CuW alloy, with the increase in arcing cycle, and microcracks initiated and then propagated into the depth mainly due to transverse stresses. During arcing, the temperature and induced thermal stress were improved because of the appearance of graded structure on the surface, and then the erosion and cracks were enhanced. Hence, the failure mechanism of CuW contact was revealed.