Circuit Description

The generator provides voltage to operate the vehicle's electrical system and to charge its battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the battery terminal.

When the engine is running, and the generator is rotating, a voltage is generated in the stator. The generator's voltage regulator senses this voltage and controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F terminal is connected internally to the voltage regulator. When the voltage regulator detects a charging system problem, it grounds this circuit which illuminates the charge indicator lamp. The system voltage sense circuit receives ignition voltage through the IG fuse in the junction block. This voltage is used by the regulator as the reference for system voltage control.

When the ignition switch is turned to ON, the charge indicator turns on for a few seconds (bulb check), then turns off. When the generator is not rotating, the regulator provides a ground which causes the charge indicator to illuminate. When the generator is rotating, the regulator provides a separate output voltage to the charge indicator. Since equal voltage is now provided to both sides of the charge indicator, the lamp loses its ground and goes out.