Suzhou Firstall Electric Machine & Technology Co.,Ltd.

Here is the rub; a car battery cannot use AC power. For that reason the alternator must first convert all the AC power to DC power so that it can then transfer that to the battery and the battery can use it for powering the electrical components of the vehicle. This is accomplished by the alternator feeding all of the AC power it generates into diodes that convert the AC to DC.
The two main components that generate power in the alternator are the rotor and the stator. As the engine runs it will rotate the alternator pulley and this causes the rotor to spin past three stator windings (wire coils) that surrounds an iron core that is fixed in place and makes up the stator. This is also known as a three-phase current.
The stator windings will be evenly spaced around the iron shaft at intervals of 120 degrees. The rotor produces an alternating magnetic field that creates an alternating current in the stator. This current will be an AC generator current which as stated earlier cannot be used by the vehicle’s battery. To address this issue, the AC current that has been generated is then sent through stator leads that go into a linking set of diodes. Both stator leads will have two diodes connected to regulate the flow of the current. The diodes then become a one way feed of DC power directly to the battery.