How does the torque fluctuation of Single Phase Motor occur?

In the field of motors, Single Phase Motor is widely used in various small devices and household appliances. However, single-phase motors often have torque fluctuation problems during operation, which not only affects the performance and stability of the equipment, but also may cause noise and vibration.
First of all, the fluctuation of power supply voltage is an important reason for the torque fluctuation of single-phase motors. Since the power supply of single-phase motors usually comes from the mains, and the voltage of the mains is not completely stable, there will be certain fluctuations. When the power supply voltage increases, the torque of the motor will increase; when the power supply voltage decreases, the torque of the motor will decrease. This torque fluctuation caused by power supply voltage fluctuation will affect the running stability of the motor, especially in occasions with high torque requirements.
Secondly, the load change of the motor will also cause torque fluctuation. When the load of the motor increases, the motor needs to output a larger torque to overcome the resistance of the load. If the load changes greatly or changes quickly, the torque of the motor may not be adjusted in time, resulting in torque fluctuation. For example, in some mechanical equipment, the load of the motor will change with the change of working state, which is easy to cause torque fluctuation.
In addition, the structural characteristics of single-phase motors can also cause torque fluctuations. Single-phase motors usually use capacitor starting or resistor starting, which will produce certain torque fluctuations during the motor startup and operation. In addition, the uneven distribution of the magnetic field of the single-phase motor will also cause torque fluctuations. Since the single-phase motor has only one stator winding, the distribution of its magnetic field is not as uniform as that of the three-phase motor, which easily leads to torque fluctuations.
In order to reduce the torque fluctuation of the single-phase motor, some measures can be taken. For example, using a stabilized power supply can reduce the impact of power supply voltage fluctuations on the motor torque; reasonably selecting the capacity and load of the motor to avoid excessive load changes; using advanced control technology, such as variable frequency speed regulation technology, the motor speed and torque can be adjusted in real time according to the load changes, thereby reducing torque fluctuations.