中文摘要：

继电器是一种重要的控制电器，其寿命及可靠性直接关系到整个控制系统的稳定性。论文首先构建了无保护电路和3种有保护电路模型并给出了电弧能量的计算公式；然后研发了继电器电寿命实验装置并通过实验研究了上述4种电路中继电器开断感性负载时触点的电弧侵蚀情况。实验结果表明：无保护电路燃弧时间最长，过电压最大，其次就是压敏电阻保护电路，在阻容保护电路和二极管阻容保护电路中，触点开断时的过电压明显小于以上两种电路的电压值，触点侵蚀量小，电寿命长，尤其是二极管阻容保护电路的电压值变化平缓，保护性能最好。最后提出了用专家系统软件通过计算电弧能量来估计继电器电寿命的新方法。

英文摘要：

Relay is used to be a kind of important control appliance, and its life and reliability are related to the stability of the whole control system. Firstly, the models of one unprotected circuit and three protected circuits were built and the formulas of arc energy for each circuit were given in this paper. Secondly, the experimental equipment of electrical life of relay was developed and the arc erosion status of contacts of breaking the inductive load with the four circuits was researched by experiments. The results of experiments show that the unprotected circuit has both the longest arcing duration and the highest over-voltage, and that of the protected circuit with Voltage Dependent Resistor （VDR） take the second place. As for the resistor-capacitor （RC） protected circuit and the RC and diode protected circuit, the over-voltage is much lower than that of the other two circuits, and the electrical life is longer for its lower erosiveness. Especially for the RC and diode protected circuit, the change of the voltage is smooth, so it has the best protection performance. Finally, a new method of compiling the expert system to calculate the arc energy and to estimate the contact electrical life was proposed.