2. In terms of structure, the former principle is relatively simple, but the structure is messy, not easy to protect; the latter principle is messy but the structure is relatively simple, easier to protect than DC motor.
3. DC motors have a static magnetic field, the conductor moves in the magnetic field; AC motors rotate in the magnetic field, and the conductor does not move.
4. In terms of speed regulation, DC motor can complete a smooth, economical speed regulation, does not require the cooperation of other equipment, only need to change the input or excitation voltage and current to complete the speed regulation; while the AC motor itself can not complete the speed regulation, need to rely on variable frequency equipment to complete the speed change.
5. The motor structure is different. DC motor is driven by direct current, so it will not directly generate rotating magnetic field. It relies on the commutator with the rotor rolling at any time to change the direction of the current into the rotor, so that the magnetic field between the rotor and stator polarity is always opposite, so that the rotor rolling; but because the AC motor uses AC power, only the stator coils are arranged in phase, so naturally produces a rotating magnetic field.