For YD series motors, there are many distinguished features, small size, light weight, satisfactory performance, easy to control and reliable in operation, as compared with the JD02 series YD motors have higher efficiency, higher power factor, higher starting performance and reduced level of noise and vibration. The YD series pole-changing motors are suitable for driving general purpose or special combination machine tools, blowers, pumps and other kinds of devices whose speed needs to be changed.