Deterioration Properties of Screwed Electric Contacts Damaged by Mechanical Vibration

摘要

Most fires due to poor contact result from a failure or misusage of electric apparatus and installation. There are many electrical connections in the electric apparatus. Poor contact happens between electrical connections by the loose and the mechanical vibration. In this paper, we have investigated thermal and electrical properties of screwed electric contacts due to the mechanical vibration. The exciter was connected to a signal generator and power amplifier that provided the vibration frequency and amplitude. The vibration, temperature and voltage data were sent to a data acquisition system(DAQ). In the case that poor contact took place, the arc happened between the screwed electric contact and electric wire, heat due to the arc was transmitted to the adjacent insulators, for which the oxide could be generated more. In addition, a spark was generated and the insulator began to melt. Thus, the possibility of electrical fire became the highest in this case. Finally, when the poor contact takes place due to vibration, the hazard of an electric accident is very high.