The difference between two-phase motor and three-phase motor

A two-phase motor is one that has only two power lines, usually one phase line and one neutral line. The working principle of a two-phase motor is similar to that of a single-phase motor, but there is an additional phase line, so a starting device is required to start the motor.

A three-phase motor is one that has three power lines, usually three phase lines. The working principle of a three-phase motor is based on the principle of electromagnetic induction, where the current rotates between the three phases, generating a rotating magnetic field, which causes the rotor to rotate. A three-phase motor does not require a starting device when starting, because the current rotates between the three phases, allowing the motor to start by itself.

1. The number of lead wires is different. A two-phase motor has two windings, so it has four lead wires, while a three-phase motor has three windings, so it has six lead wires.

2. The step angle is different. The step angle of the two-phase motor is 1.8°/0.9°, that is, 200 steps per circle, which can be subdivided into 400, 800, etc.; the step angle of the three-phase motor is 1.2°/0.6°, that is, 300 steps per circle, which can be subdivided into 600, 1200, etc.

3. The coil winding method is different. The two-phase motor coil has a main winding and a secondary winding. The winding coils of the three-phase motor are the same.

4. The working voltage is different. Two-phase motor 220V, three-phase motor 380V.

5. The starting of a two-phase motor requires the assistance of a capacitor, but a three-phase motor does not.

6. When the core size is the same, the output power is different. The output power of three-phase is large.