What is the working principle of a single-phase motor?

The working principle of the single-phase motor is to use the alternating magnetic field of the single-phase current to act on the single-phase winding. Under the action of the alternating magnetic field, the surge current in the winding generates a rotational torque, thereby making the motor rotate.

Single-phase motors generally work by generating an alternating magnetic field. Under the single-phase AC power supply, a simple rotating electric field is formed by the single-phase winding and the starting capacitor on the stator.

Multiple pole pairs are introduced into the rotor of the motor, and magnetic steel is placed around it. When the motor is running, the pole pairs of the magnetic steel will generate an alternating electric field on the stator winding under the action of single-phase current, thereby causing the rotor of the motor to rotate. .

How does a single-phase motor achieve forward and reverse rotation?

The forward rotation and reverse rotation of the single-phase motor are realized by the phase change of the AC power supply. Single-phase motors usually have only one coil and no reversing track, so it is necessary to alternately provide forward and reverse currents through an AC power source to achieve forward and reverse rotation.

The phase difference between forward rotation and reverse rotation is 180 degrees, and when the phase difference of the AC power supply is 0 degrees, the single-phase motor starts to run. When the phase difference is 180 degrees, the single phase motor will reverse.

In many countries in the world, the motor regards the phase change of the power supply as the rotation of "anode" and "cathode", so as to achieve the effect of forward rotation and reverse rotation. However, in China, forward rotation and reverse rotation are generally regarded as "forward" and "reverse", and the phase change of the power supply is described as "forward" and "reverse".

How can a single-phase motor achieve positive and negative rotation?

Single-phase motors have only one power input, so a special device is usually required to achieve forward and reverse rotation. The most commonly used forward and reverse device is an AC motor starter, which can switch the connection of power and coils in different sequences to make the motor reverse. The following are example steps to achieve forward and reverse rotation of a single-phase motor using an AC motor starter:

1. First choose a starter suitable for the motor, such as O/L (Over Load) protection will prevent the motor from being damaged due to overload when it is working.

2. Set the starter according to the characteristics of the motor such as rated voltage, current and power.

3. Determine the forward and reverse wiring of the motor and connect them to the corresponding positions on the starter to ensure the correct starting sequence.

4. Test the forward and reverse action. Before starting the motor for the first time, switch the starter to forward mode and check that the motor starts and runs correctly. Then switch the starter to reverse mode to check whether the motor can reverse normally.

5. Make adjustments to the motor. If the motor does not come to a standstill or reverse as expected, the starter setting and where it is connected can be adjusted to change the starting sequence and/or adjust how the coils are connected.

When using a single-phase motor, if the front and rear end bearings of the motor are sliding bearings, lubricating oil must be fed into the bearing area to increase the service life of the bearings. In addition, the motor should also be kept clean and ventilated, and regularly maintained and maintained to ensure its normal operation.