MOUNTING GP-ENGINE 4583132 - Caterpillar

Alternator Components
(1) Fan. (2) Front frame assembly. (3) Stator assembly. (4) Rotor assembly. (5) Field winding (coil) assembly. (6) Regulator assembly. (7) Condenser (suppression capacitor). (8) Rectifier assembly. (9) Rear frame assembly.The major components of the alternator are stator assembly (3), rectifier assembly (8), field winding (5), rotor assembly (4), regulator assembly (6) and condenser (suppression capacitor) (7).Stator assembly (3) consists of a stator core and coils. As the rotor turns, its varying magnetic field causes the stator coil to produce three-phase alternating current (AC).Rectifier assembly (8) contains three positive diodes and three negative diodes to form the full wave rectifier which is connected to the stator assembly. The 50A alternator has four positive and four negative diodes.Rectifier assembly (8) changes three-phase AC to DC and provides excitation current through three exciter diodes.Field winding (5) is a stationary coil assembly that provides the magnetic field for the rotor assembly. Rotor assembly (4) provides the north and south poles which cut the magnetic field between the rotor field winding and the stator assembly. The north and south poles are separated by non-magnetic ring (12). Regulator assembly (6) controls alternator output. It is mounted inside the rear frame assembly.The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system, and switches on and off many times a second to control the field current (DC current to the field windings) to the alternator. The output voltage from the alternator will now supply the needs of the battery and the other components in the electrical system. No adjustment can be made to change the rate of charge on these alternator regulators.Condenser (7) serves as a suppression capacitor. It protects the alternator diodes from voltage spikes. It also suppresses radio and electronic interference. Condenser (7) also contains a resistor which is in series with the condenser. The condenser is mounted in the rear frame assembly on top of the regulator assembly.Starting System Components
Starter Solenoid
A solenoid is an electromagnetic switch that does two basic operations.a. Closes the high current starting motor circuit with a low current start switch circuit.b. Engages the starting motor pinion with the ring gear.
Typical Solenoid SchematicThe solenoid has windings (one or two sets) around a hollow cylinder. There is a plunger (core) with a spring load inside the cylinder that can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is made that pulls the plunger forward in the cylinder. This moves the shift lever (connected to the rear of the plunger) to engage the pinion drive gear with the ring gear. The front end of the plunger then makes contact across the battery and motor terminals of the solenoid, and the starting motor begins to turn the flywheel of the engine.When the start switch is opened, current no longer flows through the windings. The spring now pushes the plunger back to the original position, and, at the same time, moves