AIR CLEANER GROUP 2S3087 - Caterpillar

Illustration 1 g01321353
SR5 generator example the 1600 and 1800 Frame Families Shown with Controls and Accessories
(1) Generator Center Post Bus Bar
(2) Main Stator
(3) Main Rotor
(4) Rotor Shaft
(5) Permanent Magnet Pilot Exciter (PMPE) Assembly
(6) Exciter Assembly
(7) Bearing
(8) Fan
(9) Electrical Circuit Breakers An engine supplies the power in order to turn the rotor shaft (4). The exciter rotor (6) and main rotor (3) 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 (2). 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 (3). The load voltage is controlled by varying the current that goes to the exciter field (or stator). There are two methods for excitation that are used on SR5 Generators:
Permanent magnet pilot excited (PMPE)
Internal Excitation (IE) Permanent Magnet Pilot Excited (PMPE) Generator
Illustration 2 g01321364
Generator Wiring Diagram for SR5 1800 Only
(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
(T0, T1, T2, T3) Generator Terminals and/or Generator Leads Permanent 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 are shown in the following list:
Permanent magnet (PM)
PMG stator (L5)Refer to Illustration 2.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.When the engine starts turning the "Rotating Field Assembly "(RFA), the permanent magnet (PM) induces an AC voltage in the PMG stator (L5). The PMG stator has three coils of wire. The PMG stator generates three phase alternating current (AC). The resulting AC powers the voltage regulator.Within the voltage regulator, the three phase alternating current is rectified to direct current (DC). A controlled amount of the DC current is supplied to the exciter stator (L1) through terminals F1 and F2.Direct current flows to the exciter stator (L1) which creates a magnetic field. The exciter rotor (L2) rotates in this magnetic field. The exciter stator and the exciter rotor generate three phase alternating current for the 1800 frame generators. The exciter stator and the exciter rotor