低压电器中气动斥力的实验研究

Experimental Investigation on the Blow Open Force of Low Voltage Electric Apparatus

气动斥力对于低压电器中动触头斥开后的运动状态起着重要作用,影响其性能。该文针对一个双断点模型,通过测量电弧电流、电压和作用在动导电杆上的力,应用三维有限元方法分析回路中的电动斥力,实验研究了3～6kA预期短路电流有效值,2～6mm触头开距情况下气动斥力的特性,以及产气材料和出气口大小对于气动斥力的影响。结果表明:单位电弧功率产生的气动斥力FB/ui是燃弧时间的减函数,与触头的间距关系较小,而且短路电流峰值在4kA以上时特性较为接近,加入产气材料或增大出气口均会增大气动斥力的数值。

Blow open force has important effect on the motion status of the moving contact after it separates from the static one, and which affects the performance of low voltage electric apparatus. To one double-breaker model, measuring the arc current, voltage and force acting on the moving conductor and calculating the elector-dynamic repulsion force of the conductor loop with 3-D finite element method, the characteristics of blow open force have been investigated under the conditions of 3-5 kA prospective short circuit current and 2-5 mm contact gap with the influence of gassing material and venting size. It demonstrates that the ratio between the emerging blow open force and arc power FB/ui decreases with the arcing time, the contact gap has less effect on FB/ui, and the characteristics of the blow open force are similar when the peak value of the short circuit current is beyond 4 kA. In addition, the value of the blow open force will increase with the existence of gassing material in arc chamber as well as the increase of the venting.