我发现静电感应起电机做演示实验时 ,常碰到 :不能起电 ,或火花距小的问题。我把解决问题的方法简单介绍如下。我校的感应起电机 ,有能起电的 ,但火花距不大 ,演示平行板电容器的电容大小研究时 ,指针验电器偏转角度不大 ,同样做电场线等演示时也不理想。还有的起电机不能起电 I have found that when static induction motors are used for demonstration experiments, I often run into problems where they cannot be powered or have small spark distances. I will briefly introduce the solution to the problem as follows. The induction motor of our school can be electrified, but the spark distance is not large. When demonstrating the capacitance of the parallel plate capacitor, the deflection angle of the pointer electroscope is not very large. It is also not ideal to do electric field lines and other demonstrations. There are other starting motors that cannot be electrified