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, the generator turn-on signal is sent to the generator from the PCM, turning on the regulator. The generator's voltage regulator 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 and externally to the PCM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the PCM that a problem exists. The PCM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives battery positive voltage that is Hot At All Times through the DIM fuse in the rear fuse block. This voltage is used by the regulator as the reference for system voltage control.

Limo (WC5)
This is a dual generator system, with a primary and secondary generator. The primary generator is the standard equipment generator and operates as described in the text.

The secondary generator is a smaller generator. Refer to Generator Usage. This generator is used to maintain battery voltage over an extended idle period with high loads. This generator functions the same as other generators, but is not PCM controlled.

When the engine is running power is sent to the battery positive voltage sense circuit, turning on the regulator. The regulator uses the input voltage to control the output of the generator.

The battery positive voltage output circuit of this generator is connected to the battery positive voltage terminal on the underhood bussed electrical center. The wiring harness for this generator also contains a test terminal for the lamp circuit of the generator.

"For a description of the RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at Vehicle/Application ID". RPO Codes