Secondly, the fan can't rotate because of lack of oil. You can disassemble the motor with a screwdriver and apply some lubricating oil to the shaft and sleeve to make the fan return to normal. If the fan blades do not rotate due to serious wear, the parts and shaft sleeves can be replaced.
3. Finally, it is suggested to seek the help of professional maintenance personnel to ensure safe and correct maintenance. During maintenance, please be sure to disconnect the power supply to avoid electric shock or fire.