Alternator: Description and Operation

GENERATOR (also referred to as Alternator)

DESCRIPTION
The generator is belt-driven by the engine using a serpentine type drive belt. It is serviced only as a complete assembly. If the generator fails for any reason, the entire assembly must be replaced.

OPERATION
As the energized rotor begins to rotate within the generator, the spinning magnetic field induces a current into the windings of the stator coil. Once the generator begins producing sufficient current, it also provides the current needed to energize the rotor.

The Y type stator winding connections deliver the induced AC current to 3 positive and 3 negative diodes for rectification. From the diodes, rectified DC current is delivered to the vehicle electrical system through the generator battery terminal.

Although the generators appear the same externally, different generators with different output ratings are used on this vehicle. Be certain that the replacement generator has the same output rating and part number as the original unit.

Noise emitting from the generator may be caused by: worn, loose or defective bearings; a loose or defective drive pulley; incorrect, worn, damaged or misadjusted fan drive belt; loose mounting bolts; a misaligned drive pulley or a defective stator or diode.

GENERATOR FIELD SOURCE (+) - PCM OUTPUT
This output from the Powertrain Control Module (PCM) regulates charging system voltage to the generator field source (+) circuit. The voltage range is 12.9 to 15.0 volts. Models of previous years had used the ASD relay (directly) to apply the 12 volt + power supply to the generator field source (+) circuit.

GENERATOR FIELD DRIVER (-) - PCM OUTPUT
This output from the Powertrain Control Module (PCM) regulates charging system ground control to the generator field driver (-) circuit.

GENERATOR CARTRIDGE FUSE
A 140 ampere generator cartridge fuse is secured with two screws to the input and output bus bars within the Power Distribution Center. This cartridge fuse helps to protect the vehicle electrical system from damage that could be caused by overcharging and/or excessive electrical system current due to a faulty generator or faulty charging system circuits.

If a generator cartridge fuse fails, be certain to inspect and test the vehicle charging system before replacing the fusible link and returning the vehicle to service.

The generator cartridge fuse is available for service replacement. This cartridge fuse cannot be repaired and, if faulty or damaged, it must be replaced.