为了提高加工效率(特别是自动机床),使刀具刚接触工件就立即由快速趋进转入工进,国内通常用载荷继电器来实现。当刀具碰触工件时,利用刀具电机功率消耗增加的原理,实现对速度转换的控制。但这种方法的缺点是,信号电阻设置调整困难,设备灵敏度也难以调整,且由于工作状态与电网电 In order to improve the processing efficiency (especially automatic machine tool), the tool just contacts the workpiece immediately into the work by rapid progress, the domestic load relay is usually used to achieve. When the tool touches the workpiece, the use of tool motor power consumption increases the principle of speed control. However, the shortcoming of this method is that the adjustment of the signal resistance is difficult to set, and the sensitivity of the device is also difficult to adjust. Because of the difference between the working state and the power grid