Study On The Law Of The Impact Of Contact Rotary Interruption On DC Air Arc

As an indispensable electrical component in daily production and life,low-voltage DC switch is widely welcomed by users because of its superior performance,simple structure,low price and other advantages,and has been used up to now.But in the international competition of switchgear,how to improve the technical performance index of products is the focus of current research.At present,most contacts are interrupted by linear motion mode.By changing the interruption mode of contacts,grasping the dynamic characteristics of arcs under different interruption modes of contacts,exploring the interruption mode of contacts conducive to arc extinction is of great significance for reducing arc time and arc ablation of contacts.In this paper,a scheme of contact breaking with linear motion with rotating mode is proposed,and the dynamic characteristics of the contact arc are compared and analyzed with that of the contact during the linear breaking process,aiming at the study of the influence of contact rotational breaking on DC air arc.Based on magnetohydrodynamic theory(MHD),a three-dimensional mathematical model of DC air arc is established.The comparative distribution of arc root position,arc column velocity and arc temperature during DC air arc motion is obtained by multi-physical field coupling simulation.The analysis shows that the contact linear motion with rotating mode interruption accelerates the flow of arc cylinder,accelerates the reduction of arc temperature,and is more conducive to arc extinction than the contact linear motion interruption.For contact linear motion with rotating mode interruption,the intrinsic mechanism of the difference of arc dynamic characteristics under different interruption velocities of contacts is essentially understood by means of numerical simulation calculation by changing the linear and rotational motion velocities of contacts,which is more conducive to the interruption velocity matching of contacts for arc extinction.The results show that the linear velocity of the contact is 1.2m/s and the rotation speed is 1ms and the rotation speed is 2 degrees within the speed range of this paper,which is more conducive to the extinction of the arc than the breaking speed of other contacts.In order to verify the simulation results,this paper builds an experimental platform.Highspeed camera is used to capture the arc image in the process of contact breaking.The data acquisition system is used to collect the arc voltage and arc current waveforms.The effects of different breaking modes and speeds on the arc dynamic behavior are analyzed.The experimental results are compared with the simulation results under the corresponding conditions.The simulation results are consistent with the experimental results.The research content of this paper has certain guiding significance for improving the breaking mode of low voltage electrical contacts.