Functions of an Electrical Alternator

An alternator converts one type of energy into another. An electrical alternator turns kinetic movement from a spinning crankshaft into electrical energy. Alternators look complex to those with untrained eyes, but the principles of an alternator are very simple to understand.

Inductive Power Generation

Magnetism and electricity are two forces that are needed to make an electrical alternator work. Electricity is energy made of electrons that are moving from one location to another. Kinetic energy is energy on a subatomic scale. Electrons are similar to tiny, negatively charged magnets. By applying a magnetic field to the electrons they will move toward or away the magnet. Passing a magnet through a coil of wire causes the electrons in the wire to move. This creates an electrical flow reaction, which is also called inductive generation.

AC vs DC Power

A one-way flow of electricity is known as a direct current. This means that electrons are carried in a single direction, away from the starting point. An alternating current means the electrons are going back and forth, or alternating directions.

How Alternators Work

Alternators work on an AC power model, with coil loops that are cased in a cylindrical case working with spinning electromagnets to create the power. The magnets alternate in orientation along the cylinder, which “shakes” the electrons on the coils and produces the AC power.

Rectification

Alternators use a series of diodes to covert AC power to DC power. The diodes on the alternator's negative output face allow electrons to flow into the alternator. The diodes on the positive side allow electrons to flow out, but not back in. This turns an AC signal into a one-way DC signal. The DC power leaves the alternator, recharges the battery and the car is then powered by the battery.