真空电弧截流现象的理论研究_淡淑恒.pdf

19 11 V ol. 19 No. 11 1999 11 Pro ceedings of the CSEE Nov. 1999 淡淑恒 王季梅 李宏群 闫 静 西安交通大学电气工程学院, 710049 西安 THE THEORETICAL INVESTIGATION OF CURRENT CHOPPING PHENOMENON IN VACUUM ARC Dan Shuheng Wang imei Li Hongqun Yan jing Xian iaotong University, Xian, 7 10049 China ABSTRACT T he phenomenon of Chopping current in vacuum s, , arc has been researched for a long time by all means w hile the , nature of it is still quite vague. Mr. Li T ianhe once proposed a model to ex plain the r eason why different materials have differ- ent chopping current level by means of the curves or graph to solve the model. So the result is not complicate. In this paper , r - t , t he mathematical model of single cathode spot in vacuum arc is , presented, w hich is also on basis of energy and current carrier , balance on the cathode spot, revised Mr. Li s model by adding r-t some other energy items and some new physical concepts, to calculate the micro parameters of the cat hode spot including r a- dius ( r) and temper ature ( t ) as well as , the ratio of current , carried by electrons to total arc curr ent, from the macr o ones like ar c current ( i ) and catho de potential drop ( v ) . Conse- c quently all the possible states of cathode spot can be deriv ed nu- merically, which form a reg ion in , , space, the t hree-dimen- T M561. 2 sional one. All ex istence reg i