Charging System: Description and Operation

CIRCUIT OPERATION
The Generator provides voltage to operate the vehicle's electrical system and charge the Battery. The Regulator supplies current to the field coil of the Rotor. When current flows through the field coil, a magnetic field is created. This field rotates as the Rotor is driven by the Engine, creating an AC voltage and current in the Stator windings. This AC signal is converted to DC by the rectifier bridge and available to the vehicle's electrical system at the "BAT" terminal.

The Generator must supply sufficient current to all vehicle electrical loads especially for charging the vehicle's Battery. Since the Rotor speed varies with Engine speed, the Generator must also maintain the output voltage at a constant value. The Generator's Regulator switches current to the field coil of the Rotor on or off controlling the output voltage of the Generator. When the Ignition Switch is turned to "RUN," battery voltage is supplied from Fuse 16 to the Generator at terminal "F," turning on the Regulator. If for any reason terminal "F" did not supply any current to the connection inside the Generator, the Regulator could still turn on because CKT 25 would function as a backup source of "TURN ON" current.

The Regulator switches on the field current by connecting the field coil of the Rotor to battery voltage available at the "BAT" terminal.

The field current creates a weak magnetic field in the field coil when the Engine is being started. The Regulator senses Generator rotation by detecting an AC voltage at the Stator through an internal wire. Once the Engine is running, the Regulator can monitor the internal AC voltage and DC output at the "BAT" terminal. The Regulator will then vary the current in the field coil of the Rotor as needed, to provide a constant output voltage and adequate current to the electrical system of the vehicle.

"CHARGE" WARNING INDICATOR
Battery voltage is applied to the Instrument Cluster through Fuse 20 whenever the Ignition Switch is in "RUN," "BULB TEST" or "START." A ground is provided at the Generator "L" terminal when the Regulator senses a high or low voltage condition or when the Rotor stops turning.