n the analysis of electrical quantities of operational motor,we pu t forward the current quick break protection scheme and the backup protection SCРheme,including low voltage protection,over voltage protection and landing prote ction.РAt the end,we introduce the development of motor differential motion protection device from two aspects of hardware design and software design.First we introduce the overall design of the hardware of the device,and based on the design proposed the architecture of CPU device.Then we describe the concept of software platform basedРon graphic,and bring about the subassembly logic of differential motion protection based on the plete the software development of differential motion protection.РKEY WORDS:motor;frequency conversion;differential motion protectionР万方数据