A DC motor is a motor that converts direct current electrical energy into mechanical energy. DC motors are classified into three types according to the excitation method: permanent magnet, separately excited, and self-excited, of which self-excited is further divided into shunt, series, and compound excitation. DC motors are widely used in electric drives due to their good starting characteristics, excellent speed regulation performance, smooth speed adjustment, and relatively high torque. They are found in equipment such as CNC lathes, sheet metal bending machines, injection molding machines, electric vehicles, drones, medical devices, as well as vacuum cleaners, air purifiers, and other appliances.