ROD 2198839 - Caterpillar

Introduction
The 20-SI Delco Remy alternator is brushless. The output of the 20-SI Delco Remy alternator is three phase and full wave rectified.Alternator Operation
20-SI AlternatorThe alternator is an electrical and mechanical component driven by belt rotation from the engine. It is used to charge the storage battery during engine operation. The alternator is cooled by a fan that is a part of the alternator. The fan pulls air in through holes on the sides at the back of the alternator. The air exits out the front of the alternator, cooling it in the process.The alternator converts mechanical and magnetic energy to alternating current (AC) and voltage. This process is done by rotating a high carbon steel rotor between a direct current (DC) field coil and a three phase stator. The alternating current and voltage (generated by the stator) are changed to direct current by a three phase, full wave rectifier system using six silicone rectifier diodes. The alternator also has a diode trio which is an assembly made up of three exciter diodes. The diode trio rectifies field current needed to start the charging process.A capacitor is mounted in the back of the alternator. The capacitor protects the rectifier and diode trio from high voltages. It also suppresses radio noise.Alternator Components
Alternator Components
(1) Field Coil. (2) Rotor. (3) Stator. (4) Regulator. (5) Rectifier. (6) Capacitor. (7) Diode trio.The major components of the alternator are stator (3), rotor (2), field coil (1), rectifier (5), diode trio (7), regulator (4) and capacitor (6).
Stator (3)Stator (3) consists of a stator core and windings. As rotor (2) turns, its varying magnetic field causes stator (3) to produce three phase alternating current (AC).
Rotor (2)Rotor (2) consists of two pole pieces mounted on a shaft. Rotor (2) provides the magnetic field coupling between field coil (1) and stator (3).
Field coil (1)Field coil (1) is the source of the magnetic field. The strength of the magnetic field is controlled by regulator (4) which modulates the field current. The magnetic field induces a voltage in the stator windings via rotor (2).
Rectifier (5)Rectifier (5) contains three positive (+) and three negative (-) diodes to form the full wave rectifier bridge which is connected to stator (3). Rectifier (5) changes (rectifies) three phase AC to DC.
Capacitor (6)Capacitor (6) protects rectifier (5) and diode trio (7) from high voltages. It also suppresses radio and electronic interference. Capacitor (6) is mounted in the back of the alternator and connects to rectifier (5).
Diode Trio (7)Diode trio (7) consists of three diodes. Initially voltages are generated in stator (3) by residual magnetism in rotor (2). The voltages are impressed through diode trio (7) to regulator (4); through the diodes in rectifier (5) and back to stator (3). Diode trio (7) is mounted to rectifier (5).
Regulator (4)Regulator (4) controls alternator output. Regulator (4) limits the alternator voltage to a preset value by controlling the field current. It operates electronically to alternately "turn off" and "turn on" the voltage across field coil (1). Regulator (4) acts