Introduction

This page provides information in regards to Toyota alternators.

Alternator Function

The function of the alternator is to supply electrical energy to support the electrical loads in the vehicle's electrical system such as the electronic fuel injection system, radio, lights, defogger and more.  As a number of critical loads (i.e. fuel injection system) are supported by the alternator it is important that the system is operational.

Under normal conditions the alternator is responsible for supplying all of the electrical energy required for the vehicle systems and the battery is only used to help in filtering out voltage spikes and supplying short duration of currents when heavy electrical loads are turned on (e.g electric engine cooling fans).

The alternator is also responsible for charging the battery after the engine has been started, to replace the electrical energy that was stored in the battery and used to start the engine.

Alternator Operation

In general terms the alternator is driven by the engine to turn mechanical energy into electrical energy.  I won't be exploring the details in regards to how the alternator generates electrical energy from mechanical energy in this article, however I will be exploring how the output of the alternator is regulated.

However in general terms, the alternator should output a fixed voltage regardless of the electrical load (current draw) of the vehicle systems, that means that the alternator should be able to keep the same output voltage when the lights and defogger, etc are on (heavy electrical load) as when the lights and defogger, etc are off (small electrical load).

If the alternator wasn't able to regulate it's output, and it's output was fixed (a fixed output current) you would find that while the alternator output voltage when the alternator was under heavy load maybe acceptable, that when the alternator was under low load the output voltage would be very high and could cause damage to the vehicle's electrical system.

Views: