Parts

• An alternator has two parts: the rotor and the stator. The stator is formed from one or more stationary coils of wire. The rotor is a coil of wire wrapped around an iron core, mounted on an axle and connected to a battery.
  
  

Speed

• The rotor's axle is connected to other devices to make it rotate. In a car, it is turned by the car's engine. In a wind turbine, it is turned by a propeller. The faster the rotor turns, the greater the voltage produced.
  
  

Stator Construction

• The greater the number of turns in the stator coil, the greater the voltage the alternator generates. This is because each loop makes its own contribution to the voltage.
  
  

Rotor Current

• The higher the current in the rotor coil, the greater the voltage the alternator produces.
  
  

Warning

• Alternators are used to charge batteries and are usually made to be self-regulating. This means that they stop producing voltage when the batteries are fully charged.