How do ac motors keep moving in the same direction?
Typically by capacitance phase out another phase Angle difference of alternating current (ac) effect on the secondary coil and main coil integrated into a rotating magnetic field up to cut off the secondary coil. As for the synchronous motor, the principle of some trouble, basic is asynchronous motor rotor into a rotor as dc motor. When it starts to become asynchronous start, starts in electricity, the rotor into sync, ha ha, also forgot to tell you that a speed ratio of the motor is rotating magnetic field of low speed asynchronous motor, the same is called synchronous motor, the speed of the rotating magnetic field is the synchronous speed.
Most of the ac motor rotor is not current, power is in the little excitation current of synchronous motor synchronous runtime. Running in the rotor is current, this is in a rotating magnetic field induced current, the rotation of the rotor is also want to rely on the induced current, this is because the wire out of the current is induced in a rotating magnetic field, and wire in the magnetic field force, thus the rotor to turn up, until than the speed of the rotating magnetic field of the lower speed stability, this is the principle of asynchronous motor, so as long as the rotating magnetic field to the same, the motor to the same, how to obtain a rotating magnetic field, a direct current is not, the formation of the three-phase alternating current (ac) is itself a generator stator induced current in the rotor rotating magnetic field, so as long as he is input into the coil on the difference of 120 degrees, can be formed on the stator rotating magnetic field, single phase is somewhat hard to understand, but if you can put the sinusoidal magnetic field is decomposed into two same size changes, in the opposite direction of the synthesis of two rotating magnetic field results, as long as the rotor turns up later, and two the relative speed of the rotating magnetic field induced by the electric current cannot be integrated to zero, still can go up, just start up more troublesome.
Because the working principle of ac motor is formed stator rotating magnetic field, and then the rotor itself is a closed coil (induction motor) or a magnet (PMSM), the turning of the rotor only related to the direction of rotation of the magnetic field, magnetic field direction of rotation has been unchanged, it remains the same. This principle understanding more complicated than the direct current machine, single phase motor, in particular, the more complex, but the structure is simple. Can't use the principle of the dc motor to use ac motor, dc motor of main current is the same to the rotor, need to brush for phase to ensure the consistency of the turning of the rotor, and the ac motor is the main current to the stator, in order to form a rotating magnetic field.
There are books in the book. Do you mean to change direction and change direction? Ac motor subrotors and stators The current changes in two current directions It's going to change the same way
