Before that, let's first understand the characteristics of some single-phase motors and three-phase motors. Single-phase motor: There are two coils in a single-phase motor, the main coil and the auxiliary coil. When a single-phase sinusoidal current passes through the main coil, the main coil will generate an alternating pulsating magnetic field. The strength of this magnetic field changes with time as the sinusoidal current changes, but its direction is always 1-3. If there is no force provided by other coils, the motor will not rotate after 90 degrees. If you want to make him rotate, you must add a force perpendicular to the direction of the main coil, which is provided by the start coil, which is the auxiliary coil. If you want the auxiliary coil to provide a force perpendicular to the direction of the main coil, you must pass another phase current to the auxiliary coil.
If the same phase current is passed in, then the direction of their force generation is also the same. But there is only single-phase electricity, what should we do? At this time, capacitor phase shift is used. Simply put, it is to connect the capacitor in series in the circuit that needs to be phase-shifted, so that the current phase can be changed. After the single-phase alternating current is phase-shifted, its waveform diagram becomes like the one shown below. Finally, put it together, the motor wiring diagram is like the following figure. First, the sinusoidal alternating current comes in from point A, part of which supplies power to the main coil, and the other part is phase-shifted through capacitors.
Since the phases of the two-phase electricity are one after the other, the magnetic field force generated by the coil will also be one after the other. In this way, it is possible to push the main coil once, then push the auxiliary coil, and finally rotate. If you want the motor to reverse, you only need to change the power cord connected to point A in the above figure to point B, and the power cord connected to point C does not move. Because before the replacement, the main coil used the sine alternating current with zero phase, and the secondary coil used the sine alternating current after the phase shift. After the power cord is changed to point B, the secondary coil uses a sinusoidal alternating current with zero phase, and the main coil uses a sinusoidal alternating current with phase shifted. If the phase of the current of the two coils changes, the direction and rotation of the magnetic field force generated by them will also change.
Three-phase motor: The three-phase motor adopts three-phase AC power supply. Because of the three-phase AC power, their phase difference is 120°. When the stator winding is connected to three-phase alternating current, a rotating magnetic field will be generated in the stator. When the rotating magnetic field cuts the rotor windings, then the rotor windings will generate induced currents. The induced currents will be subjected to electromagnetic force in the rotating magnetic field and will rotate.
Three-phase motors use three-phase power, and their phase difference is 120 degrees. We can simply understand that a Precision Cycloidal Gearbox Factory is equivalent to three people standing at three different angles to push the rotor. Single-phase motors use single-phase power and capacitors, and the phase difference between the primary and secondary coils is 90 degrees. We can simply understand that a single-phase motor is equivalent to two people standing at two different angles to push the rotor. Therefore, a three-phase motor with the same power has a larger torque (rotational force) than a single-phase motor. Therefore, if there is a three-phase power supply, try to use a three-phase motor, because a three-phase motor of the same power has the advantages of smaller size, lighter weight, lower noise, lower price, and higher torque than a single-phase motor.
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