The excitation mode of DC motor is DC input, which generates a fixed magnetic field, and the speed and torque of the motor are controlled by changing the magnetic field intensity. The advantages of DC motor are large starting torque, wide speed range and easy control. However, DC motor needs regular maintenance and battery replacement, which is not suitable for long-distance transmission, because electric energy will be lost with the increase of transmission distance.
The excitation mode of AC motor is AC input, which produces changing magnetic field. The speed and torque of the motor are controlled by changing the magnetic field strength and rotating direction. The advantage of AC motor is that it does not need to replace the battery, is suitable for long-distance transmission, and can realize energy-saving operation. However, AC motors need to be controlled by frequency converters and other equipment, and the speed regulation range is relatively small.
In addition, there are differences between DC motor and AC motor in structure and application scenarios. For example, the structure of DC motor is relatively simple and suitable for low-power occasions, while the structure of AC motor is relatively complex and suitable for high-power occasions.