Research On The Laboratory Simulation Method Of The Influnce Of Dust On Electrical Contact

There are numerous electric contacts in electronics, electric-power and automatic control system. From reliability theory we know that each pair of electric contact is established in series as one electronic device in the electric circuit system. The reliability of electronics devices and wirings is badly influenced by the capability of electric contacts. Contact interface can be polluted by caustic medium and dust in the air. That would cause bad electric contacts which in turn would reduce the reliability of the equipments and even a breakdown. Therefore the study on the mechanism of electric contacts failure, the influence of electric contacts failure on signal transmission and how to increase the reliability of electric contacts are the premises to improve the reliability of the electronic and electrical systems.As a pre-research of mechanisms of contact failure caused by dust, this thesis has studied the electrification and motion of dust particles. According to the state of contact, it is confirmed that electric field, heat and micro-motion are the most important factors influencing the deposition of dust particles on the contact area. The method of finite element analysis has been used to find how the electrical field and heat field of the electrical contact has influenced dust particles deposition on the contact area. Laboratory equipments are also utilized in the simulation experiments. From the analysis and laboratory simulation, it was shown that the electric field do most influence in the deposition of dust particles on the contact areas and the affect of joule heat produced by the working contact resistance of the contact point is also easy to be seen.For the analysis, it is necessary to reproduce the failure; certain equipments are needed to accelerate the processes in the laboratory. Therefore, the development of the dust chamber and the analysis of the flow and distribution of the air in the chamber are vital for the study. The analysis of the air flow and distribution has been performed by the ANSYS software. The research and development of dust chamber as well as the analysis of its inside air flow would become a new method of laboratory simulation for future analysis of electrical contact failure.