When the rotor core is pressed into the rotating shaft, the outer circle of the rotor core is also required to be refined, and the main processing technology is as follows: the outer circle of the rotor and the bearing file should be in the coaxial line, otherwise it will cause the eccentricity. The size precision and finish of the outer circle of the rotor should be in accordance with the requirements of the drawings, otherwise it will cause the air gap is too large or too small, which affects the motor performance. Rotor dynamic balance if the difference will cause the sound, vibration. Technical requirements