Alternator parts and function


Familiarize yourself with the alternator parts and function



At the end of the lesson the students should be able to:

Identify the parts of alternator.

The importance of alternator in cars.

Demonstrate the function of alternator parts.



Parts and function of alternator 

Technically speaking, an alternator converts mechanical energy into electrical energy through a process known as alternating current. Alternators are electrical generators

How alternators work to make electricity

The alternator has three main components and a voltage regulator: The Stator, Rotor, and Diode. When the alternator belt or V-belt spins the pulley on the alternator, the rotor inside the alternator spins fast. The rotor is basically a magnet or group of magnets that spin, with all that speed, inside a nest of copper wires, which are called the stator.



The first part of alternator is pulley. The pulley function is to rotate the rotor assembly as the engine is running. Yes, the pulley works as a connector between the rotor assembly and the engine through a drive belt were known as alternator belt or serpentine are three types of alternator pulley, solid pulleys, one-way clutch pulleys (OWCs), and overrunning alternator decoupler pulleys (OADs). Even they have different types, but the function is still remain the same; to rotating the rotor assembly as the engine runs.


     The second part of alternator is housing. The housing function is to protect the inner parts of alternator and become a house hold of them like stator, bearings, rectifier, and so on.The housings are splitted into two parts, front housing and rear housing. Front housing is located near the pulley while the rear housing is at the opposite. Between of them there is a stator assembly body.


 The third part of alternator is bearings. The bearings function is to make the rotor assembly rotate freely, they attached in front of and at the end of the rotor shaft. They support the rotor shaft so the rotation runs smooth and freely.These bearings sits on the alternator housing. Front bearing is attached on the front housing and the rear bearing is attached on the rear housing.

4.Rotor assembly

The fourth part of alternator is rotor assembly. The rotor assembly function is to generate magnetic field by electromagnetic force were built up because the electric current flows from the battery through the rotor coil.When the rotor assembly is spinning, the magnetic field will cut the stator coil. As the magnetic field cuts the stator coil, the stator coil generates electricity energy. More faster the rotor rotations, it's increasing the electric current were generate in stator coil.

5.Stator assembly

The fifth part of alternator is stator assembly. The stator assembly function is to generate electric current as the rotor assembly (being electromagnetic) cuts the stator coil. The stator is a stationary set of windings that surrounds the rotor. The coil build in rounded shapes so the rotor assembly can rotate inside the stator coil.



Activity 1

Enumerate the different parts of alternator, its function based on your understanding.


Activity 2 Essay type

What is the importance of Alternator in our cars?