During the breaking process of a vacuum interrupter, there is a time interval between current zero and generation of recovery voltage. This time interval is variable and matters to the calculation of continuous transition model, but always simplified as a constant. In this article, we put forward the concept of preparatory stage of sheath, analyze the production mechanism and influence on breaking ability, and give the computation method for the duration of this stage. In order to verify the rationality of the theoretical analysis and calculation method proposed in this article, experimental measurement is conducted. The experimental results are in good agreement with the values of duration calculated by the theoretical formula in this article in terms of magnitude and variation law.

中文翻译：

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真空灭弧室间断鞘的准备阶段研究

在真空灭弧室的断开过程中，电流零与恢复电压的产生之间存在一个时间间隔。该时间间隔是可变的，对连续过渡模型的计算很重要，但始终简化为常数。本文提出了护套准备阶段的概念，分析了护套的生产机理及其对断裂能力的影响，并给出了该阶段持续时间的计算方法。为了验证本文提出的理论分析和计算方法的合理性，进行了实验测量。实验结果与本文理论公式计算的持续时间值在大小和变化规律方面非常吻合。