ROD AS 1163512 - Caterpillar

Alternator Operation Schematics
The electrical schematics indicate terminals and basic circuitry for the K1 and N1 series alternators are as follows.
Illustration 1 g03240197
K1 Series Alternator Schematic (12V)
Illustration 2 g03240198
K1 Series Fully Enclosed Alternator Schematic (12V)
Illustration 3 g03240199
N1 Series Alternator Schematic (24V)All N1 series contains power output diodes. There is one positive (+) and one negative (-) diode that increases the power output by approximately 15%.The alternator has three circuits such as the charging circuit, excitation circuit, and the pre-excitation circuit. The description of the circuits is as follows:Charging Circuit
Current for battery charging and for the electrical accessories is taken from the B+ terminal of the alternator. The flow of current for battery charging and electrical accessories at an instant of time (120° phase angle) is shown in illustration 4 Phase Relationships (120°).
Illustration 4 g03240216
Charging circuit with phase angle of phase "U" = 120°Voltage at the output of winding "U" is positive, negative at winding "W" and zero at winding "V" (no voltage). The current path is as follows:Output from winding "U" through positive diode "U", alternator terminal B+, battery ground, alternator terminal D-, negative diode "W", output of winding "W" to the neutral point.
Illustration 5 g03240236
Charging circuit with phase angle of phase "U" = 150°If another time instant is chosen (150° phase angle) where none of the voltages are zero, the current would flow as shown in illustration 5 Phase Relationships (150°).Equal currents flow from windings "U" and "V" to the respective positive diodes. They return to the neutral point through "W" winding negative diode and winding "W".Note: Not all the diodes belonging to the various phases are used at the instant of time examined in this example. This remains true for all the other instants of time which could be examined. Individual phase currents change in magnitude and polarity, while the output current to the battery or electrical accessories remains uniform.Excitation Circuit
The exciting current for generation of the magnetic field is taken from the stator winding. It is rectified by three exciter diodes and the three negative power diodes. The exciting current follows the path shown in the illustration 6.
Illustration 6 g03240256
Excitation circuit with phase angle of phase U = 120°Current flows from the output of winding "U" (positive at this instant of time), through its corresponding exciter diode and the alternator D+ terminal to the regulator D+ terminal. When the regulator is turned on, current then flows to the regulator DF terminal to the excitation winding by the way of terminal DF of the alternator. Current then flows to the alternator terminal D- and the negative power diode to winding "W" (negative at this instant of time) completing the circuit at the neutral point.Pre-excitation Circuit
When in operation at high speed, the alternator is self-excited. Excitation current for the magnetic field is obtained from the main current. However, when initially starting, the alternator depends on residual magnetism. When the current of an electromagnet is disconnected, the magnetic field does not disappear completely. The iron core remains slightly magnetic. This is called residual magnetism. There