LOCK-RETAINER 2B9018 - Caterpillar

An engine supplies the power in order to turn the rotor shaft. The exciter rotor and main rotor windings are attached to the rotor shaft. The voltage regulator supplies DC current to the exciter field (stator). As the rotor shaft turns, the exciter rotor generates AC current. The rectifier components convert the AC exciter current to DC current. This DC current is supplied to the main rotor windings. A magnetic field is created around the poles of the main rotor windings. As the main rotor turns with the rotor shaft, the magnetic field also rotates.The magnetic field induces an AC voltage into stationary main stator. The main stator is a coil with multiple turns of wire. The current that flows through the main stator flows to the load.The rectifier assembly will supply DC current to main stator. The load voltage is controlled by varying the current that goes to the exciter field (or stator). The Series LC generator uses a field excitation system to regulate the output voltage of the generator. The automatic voltage regulator (AVR) will monitor the output voltage of the generator. The AVR automatically adjusts the current in the field excitation system in order to maintain the correct output voltage.There are three methods for excitation that are used on LC5000, LC6100 and LC7000 generators:
Shunt
Auxiliary winding regulation excitation principle (AREP)
PMGShunt Generator
Illustration 1 g02175074
Shunt generator wiring exampleAVR Shunt Field Excitation
Shunt field excitation uses the AVR for the exciter field.Shunt field excitation uses power from the main windings of the generator to power the AVR. The generator with shunt field excitation is self-excited. The AVR monitors the excitation current of the exciter as a function of the generator output voltage. The generator with Shunt field excitation is simple in design. The generator with Shunt field excitation is not capable of sustaining a short circuit.Permanent Magnet Pilot Excited (PMPE) Generator
The PMPE, also known as PMG, excited generators use the AVR for regulation of the exciter field.
Illustration 2 g02175065
PMPE generator wiring diagram example (CR1 - CR6) Diodes (CR7) Varistor (L1) Exciter Stator (L2) Exciter Rotor (L3) Main Rotor (L4) Main Stator (L5) PMG Stator (PM) Permanent Magnet (R5) Resistor (RFA) Rotating Field Assembly (TR1) STD Voltage Droop Transformer (optional) (T0, T1, T2, T3) Generator Terminals and/or Generator LeadsPermanent magnet pilot excited (PMPE) generators receive power for the voltage regulator from a pilot exciter. Internal excitation generators receive power for the voltage regulator from auxiliary windings that are embedded in the stator slots. The PMG components consist of a permanent magnet (PM) and a PMG stator (L5) .The pilot exciter operates independently from the generator output voltage. Constant excitation during a large load application is possible because the irregularities that occur in the generator output voltage do not affect the exciter.The irregularities that occur in the generator output voltage are caused by load conditions. The independent exciter operation also allows the generator to sustain excessive currents for short periods of time.Wh