Charging System: Description and Operation

OPERATION
The power source of the charging system is the alternator. Current is transmitted from the field terminal of the regulator through a slip ring to the field coil and back to ground through another slip ring. The strength of the field regulates the output of the alternating current. This alternating current is then transmitted from the alternator to the rectifier where it is converted to direct current.

These alternators employ a three-phase stator winding in which the phase windings are electrically 120° apart. The rotor consists of a field coil encased between interleaved sections producing a magnetic field with alternate north and south poles. By rotating the rotor inside the stator, the alternating current is induced in the stator windings. This alternating current is rectified (changed to DC) by silicon diodes and brought out to the output terminal of the alternator.

CIRCUIT OPERATION
The charging system is an integral part of the battery and starter systems. Since all of these systems work together, any diagnosis and testing should be done in conjunction.

The charging system is protected by a 12 gauge fusible link located in the A11 circuit. This fusible link is between the generator and the starter.

The generator ground is provided through a case ground in the generator to its attaching bracket. This generator uses a voltage regulator internal to the Powertrain Control Module (PCM).

When the vehicle is running, battery voltage is applied to the generator field terminal through the A142 circuit. This circuit is the output from the contact side of the Automatic Shut Down (ASD) relay The ground, or voltage regulated side, of the generator field is controlled by the K2O circuit which connects to cavity 4 of the PCM connector.

When there is current present in the field, and the rotor is turning, the stator in the generator produces a B+ voltage that is supplied to the battery through the A11 and A0 circuits. The A11 circuit is connected to the output terminal of the generator and connects to the engine starter motor battery feed terminal. The A0 circuit is a direct feed line from the battery and connects to the engine starter motor.

Grounding for the system is accomplished at the battery negative terminal. These grounds connect to the engine and body.