Theoritic And Experimental Study On The Rules And Mechanism Of Arc Two Phase Transition

Relay, as one of main electronic components for control, information transfer and circuit switch, is widely used in the field of aerospace and aviation. Now having big capacitance and high reliability are the main current in the design of relay contact, one of the important components of relay is very simple, but it's fault as a result of the arc that is coming into being when the contacts are closing or opening is very serious. So, It is of very theoretic significance and practicality worth to investigate on the mechanism of how breaking arc generates, develop and on the characteristic of it, to suffice for keeping up the life and the reliability with the improvement on the open capacitance. The discussion on the arc burning mechanism is necessary for the research on contacts'arc corrosion. But, because of the low voltage and low current, the arc can not last long duration. It has remarkable nearing cathode space effect and the transformation from metallic phase to gaseous phase. It has very important significant to research the mechanism of two phase transition. This paper, which is based on the load experiments, emphasizes on the Change rules of arc characters: arc time and Platforms'voltage, and discusses the mechanism of two phase transition.First, the experimental circuit and plan were designed. The load experiments were carried on in air condition, under 36V voltage. Then, the waveforms were used to definite the two arc stages and the their characteristic parameters: each arc time and voltage values of arc platforms. Carrying on the two characteristic parameters, the relationships were Obtained from total arc time, metallic arc time, gaseous arc time, initial voltage and average voltage on each phase to current. The experiments indicate that: total arc time increases with current by three stages, each state presents for good linear relation; metallic arc time increases with current by Index relation, and it has the saturated tendency and big dispersivity; total arc time had large growth when gaseous phase arc appearances, and gaseous arc time has smaller dispersivity; metallic phase arc voltage initials by about 12V, and has slight rise with the current growth; gaseous phase arc voltage initials by about 24V; each phase platform voltage has the trend of escalation when current is slightly bigger. Last, the two phase transition theory was discussed based on the experimental results. The experiments indicate that: each platform initial voltage is corporate with the sum of the electron's leisure potential, ionization and excitation potential of metal vapor and gas, and the latter is the space charge area potential of anode and cathode., the former is always bigger than the latter because of the Arc column potential drop; there is a critical gap when the arc two phase transfer.