When driving a stepper motor, if you notice significant noise emanating from within the motor when it’s in a stationary state, resembling rapid changes in coil activity, it is often due to the motor operating in an oscillation zone.

1. Causes of Stepper Motor Vibration and Noise from the Driver Circuit:

1. 1. • (1) Fluctuations in the power supply;
      • (2) Waveform of excitation current;
      • (3) High harmonic content in the stator current (occurs during subdivision);
      • (4) Imbalance in phase currents, especially in non-constant current control states.

      The primary cause is often the high harmonic content in (1). Stepper motors, when driven by square-wave currents, inherently produce a significant amount of high harmonics, leading to vibration and noise. Therefore, it’s preferable to use sinusoidal wave currents. Subdividing the stepper motor is a method that approaches sinusoidal wave drive.

1. Causes of Stepper Motor Vibration and Noise from the Motor Itself:

1. 1. • (1) High harmonic components in the excitation power source;
      • (2) Tooth slot torque;
      • (3) Vibration noise caused by rotor deformation due to radial magnetic attraction.

      In conclusion, when selecting a stepper motor, it’s advisable to choose one of relatively higher quality. This minimizes the probability of malfunctions, making the application more reliable with lower maintenance costs.