How does phase rotation or reversal apply to a single-phase equipment?

Application of Phase Shifting or Inversion in Single-Phase Equipment

Single-phase equipment changes the rotation direction of the motor through phase rotation or inversion, which is an important means to achieve flexible control of the equipment. The following is a detailed explanation of this process and its specific applications:

1. Basic Principles of Phase Shift

The working principle of a single-phase motor is to use the alternating magnetic field generated by a single-phase AC power supply to induce a rotating magnetic field through the stator coil, which in turn drives the rotor to rotate. Single-phase motors usually have one main winding and one starting winding, and a starting capacitor is often connected in the starting winding to produce a phase shift, thereby starting the motor and making it turn.

2. Methods for Phase Rotation

2.1 Phase Connection of Switched Power Supply

• Method: In a single-phase power supply, the two phases of alternating current are marked as "L" (live wire) and "N" (neutral wire). By swapping the connections of the two phases, "L" and "N," the rotation direction of the motor can be changed.

• Operating Steps:

1. Cut off the power supply to ensure safety.

2. Find the coil terminals of the motor, usually marked with color.

3. Swap the connections of "L" and "N" phases.

4. Reconnect the power and test the rotation direction of the motor.

2.2 Change the Connection Method of the Starting Capacitor

• Method: In single-phase motors, starting capacitors are used to generate a phase-shifted magnetic field to start the motor and make it rotate. By changing the connection method of the starting capacitor, the rotation direction of the motor can be changed.

• Operating Steps:

1. Cut off the power supply to ensure safety.

2. Find the starting capacitor of the motor.

3. Change the starting capacitor connection method, usually involving swapping the capacitor's connection with the winding.

4. Reconnect the power and test the rotation direction of the motor.