【摘要】 对小电流冷阴极真空电弧的单个阴极斑点建立了以能量平衡、离子守衡为基础的数学模型，将真空电弧的电流ｉ、阴极压降ｖｃ 这些宏观参数与阴极斑点的半径ｒ、温度ｔ 及电子电流占总电流的比例ｓ，这些微观参数联系起来，并对铜和银分别研究了电弧电流对阴极斑点状态的影响，而且比较了铜和银在相同条件下阴极斑点的所有可能状态。发现对同种阴极材料电弧电流越大则阴极斑点可能的存在状态越多，在标度相同的ｒ－ ｔ 平面上存在的点越多，点堆积成的图形面积也越大。在相同的电弧电流下的不同触头材料，截流水平越低阴极斑点可能存在的状态越多，因此提出了用相同标度下ｒｔ 平面上的阴极斑点可能的存在状态面积作为衡量真空电弧相对稳定性的标准。这为比较不同触头材料截流水平相对大小提供了简便方法，有利于对低截流值触头材料的研究。更多还原

【Abstract】 The phenomenon of Chopping current in vacuum arc has been researched for a long time by all means while the nature of it is still quite vague. Mr.Li Tianhe once proposed a model to explain the reason why different materials have different chopping current level by means of the curves or graph to solve the model. So the result is not complicate. In this paper the mathematical model of single cathode spot in vacuum arc is presented, which is also on basis of energy and current carrier balance on the cathode spot, revised Mr.Li’s model by adding some other energy items and some new physical concepts, to calculate the micro parameters of the cathode spot including radius ( r ) and temperature ( t ) as well as ,the ratio of current carried by electrons to total arc current, from the macro ones like arc current ( i )and cathode potential drop( v c ). Consequently all the possible states of cathode spot can be derived numerically, which form a region in ,, space, the three dimensional one. All existence region is similar in shape for different arc current and cathode potential drop while the volume of the region is different. So only the projected area, the two dimensional graph on coordinate plane can be on half of the space region. The number of states of the cathode spot, which hint the area of existence region, increases when arc current increases or decreases when arc current does. After several contact material is surveyed, it is found that the number of states falls to zero as the result of current chopping. The order of state number is consistent with the order of chopping current level of contact materials. The regularity of the number or the projected area on plain describing all possible states of cathode spot is in accord with the trend of vacuum arc stability and the law of current chopping. So the existence area on plain can be used as the criterion of the relative stability of vacuum arc and the chopping current level of contact materials. This innovative and convenient method can make comparing the vacuum arc stability or the chopping current level of contact material more easily and can provide a new way to develop cathode materials with low chopping current.更多还原