The difference between DC motor and AC motor:

1. The motor whose speed is proportional to the voltage is a DC motor. The motor whose speed and frequency are proportional is called AC motor.

2. The DC motor is commutated by coil, and the AC motor is phase-transformed.

3. DC motor is voltage regulation, and AC motor is frequency control, which is the watershed of DC motor and AC motor.

4. The fundamental difference between a DC motor and an AC motor is that the potential balance equation is different:

1) The potential balance equation of the DC motor is: U=CΦn

2) The potential balance equation of the AC motor is: U=CΦf

3) DC motor has fast response, large starting torque, and can provide rated torque from zero speed to rated speed. However, the advantage of DC motor is also its shortcoming, because DC motor should produce rated load. For constant torque performance, the armature magnetic field and the rotor magnetic field must be maintained at 90°, which is achieved by carbon brushes and commutators. Carbon brushes and commutators generate sparks and toner when the motor rotates. In addition to damage to the components, the use is also limited. AC motors do not have carbon brushes and commutators. They are maintenance-free, rugged, and widely used. However, to achieve the equivalent performance of DC motors, complex control technology can be used. The three-phase asynchronous motor has a simple structure, reliable operation and low cost.