Principles of Operation

PRINCIPLES OF OPERATION

With the key in the ON position, voltage is applied through the warning indicator I circuit VDC42 (GN) to the voltage regulator. This turns the regulator on, allowing current to flow from battery sense A circuit SDC02 (RD) to the generator field coil. When the engine is started, the generator begins to generate alternating current (AC) which is internally converted to direct current (DC). This current is then supplied to the vehicle's electrical system through the output circuit SDC02 (RD) (B+) terminal of the generator.

Once the generator begins generating current, a voltage signal is taken from the generator stator and fed back to the regulator through the external stator circuit CDC15 (VT) or the internal stator circuit (depending on the generator application). This voltage feedback signal (typically half the battery voltage) is used to turn off the warning indicator.

With the system functioning normally, the generator output current is determined by the voltage of the A circuit SDC02 (RD). The A circuit SDC02 (RD) voltage is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain the correct generator output.

The set voltage varies with temperature and is typically higher in cold temperatures and lower in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.

This is a System 1 charging system, which uses the circuit coming from the charging system warning indicator in the instrument cluster as the I-Line control input to the generator regulator, circuit VDC42 (GN). System 1 charging systems are virtually identical in design and therefore, share the same diagnostics. The circuit numbers and colors may be different, but the functions are the same. System 1 charging systems may use any type of generator, as the generator type usually depends on the engine packaging and/or output requirements versus cost.

Circuit Description

Battery Positive Output Circuit (B+) SDC02 (RD)
The generator output is supplied through the battery positive output (B+) terminal on the rear of the generator to the battery and the electrical system.

I Circuit VDC42 (GN)
The I (ignition) circuit VDC42 (GN) is used to turn on the voltage regulator. This circuit is powered up with the key in the ON position. This circuit is also used to turn the charging system warning indicator on if there is a fault in the charging system operation.

S Circuit CDC15 (VT) (3.0L and 4.0L engines)
The S (stator) circuit CDC15 (VT) is used to feed back a voltage signal externally from the generator stator to the regulator. This voltage feedback signal (typically half the battery voltage) is used by the regulator to turn off the charging system warning indicator. This circuit is internal to the generator on the 2.3L application.

A Circuit SDC02 (RD)
The A circuit (battery sense) SDC02 (RD) is used to sense battery voltage. This circuit is used by the regulator to determine generator output. This circuit is also used to supply current to the generator field, which determines generator output.