Description & Operation

The generator features the following major components: The delta stator, rectifier bridge, rotor with slip rings and brushes, a conventional pulley, and regulator. The pulley and fan cool the slip ring and the frame. The generator features permanently lubricated bearings. Service should only include tightening of mount components. Otherwise, replace the generator as a complete unit.

The voltage regulator controls the rotor field current in order to limit the system voltage. When the field current is on, the regulator switches the current on and off at a rate of 400 cycles per second in order to control radio noise and 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.

The generator provides voltage to operate the vehicle's electrical system and to charge it's 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 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 engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once 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 PCM. When voltage regulator detects a charging system problem, it grounds this circuit to signal PCM that a problem exists. The PCM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives B+ voltage that is Hot At All Times through the GEN BAT fuse in the underhood junction block. This voltage is used by the regulator as the reference for system voltage control.