For 1990-2009 cars

### Generator

The generators feature the following major components:

• | The delta stator

• | The rectifier bridge

• | The rotor with slip rings and brushes

• | A conventional pulley

• | Dual internal fans

• | A voltage regulator

The pulley and the fan cool the slip ring and the frame.

The generator features permanently lubricated bearings. Service should only include the tightening of mounting components. Otherwise, the generator is replaced as a complete unit.

### Regulator

The voltage regulator controls the field current of the rotor in order to limit system voltage. The regulator switches the current on and off at a rate of 400 cycles per second in order to perform the following functions:

• | Radio noise control

• | Obtain the correct average current needed for proper system voltage control

At high speeds, the on-time may be 10 percent with the off-time at 90 percent. At low speeds, the on-time may be 90 percent and the off-time 10 percent.

### Charging System Indicator

The charge indicator illuminates in the IPC when the following occurs:

• | The generator output is less than 11 volts or more than 16 volts.

• | The displays test is performed in the IPC at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

• | The ignition is ON, with the engine OFF.

### Circuit Description Battery Isolator

When the Ignition switch is placed in the RUN position B+ is supplied battery isolator control circuit. The battery isolator is used to isolate the auxiliary and primary batteries. When the Ignition is OFF only the auxiliary battery is being used so that the primary battery is not being discharged causing a no start condition. When the engine is running the generator(s) recharge all the batteries to maintain system voltage and keep the batteries charged.

### 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 ECM/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 ECM/PCM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM/PCM that a problem exists. The ECM/PCM monitors the generator field duty cycle signal circuit, and adjusts the system voltage depending electrical load. On Vehicles that have a auxillary generator the ECM/PCM uses the GEN 2 turn on signal to control the auxillary generator, the auxillary generator regulator does not use a F terminal. The two generators work together to maintain system voltage.