BODY 6Y7481 - Caterpillar

Operation Of Generator
SRCR GENERATOR WIRING DIAGRAM A1 Regulator AssemblyC1 Surge CapacitorCR1 Control RectifierCR2 Control RectifierCR3 Power RectifierCR4 Power RectifierCR5 Field RectifierCR6 Build-Up DiodeCR7 Surge Suppression DiodeCR8 Surge Suppresion DiodeCR9 Blocking DiodeE1 Main Heat SinkE2 Build-Up Heat SinkE3 Auxiliary Heat SinkF1 FuseF2 FuseFL1 Noise Suppressor AssemblyK1 Build-Up RelayL1 Filter ChokeL2 Sensing ReactorL3 Revolving FieldL4 StatorR1 Regulator Gain ResistorR2 Regulator Gain PotentiometerR3 Voltage Droop PotentiometerR4 Voltage Level PotentiometerR5 Resistance WireR6 Surge ResistorT1 Isolation TransformerT2 Voltage Droop TransformerT3 Regulator TransformerTB1 Terminal BlockIntroduction
The Statically Regulated Controlled Rectifier Generator gives improved performance and longer service life by applying a method of excitation which is controlled by an automatic voltage regulation system that contains no moving parts. The generator voltage build-up system uses only one moving part: a relay, which operates only when the generator is started or shut down.Generation Of Voltage
The generator is constructed with the armature coils wound on stator (L4) and the field coils wound on the rotor, designated in the wiring diagram as revolving field (L3). The field coils are wound on magnetic steel that will retain a small amount of residual magnetism. The revolving field is connected directly to the engine flywheel through the generator shaft and coupling.As the engine turns revolving field (L3), a small amount of alternating current voltage is generated in stator (L4) by the influence of residual magnetism in the revolving field. A portion of this alternating current (AC) is rectified to direct current (DC) and this portion is directed back to the revolving field to increase its magnetism. The procedure of excitation can be traced on the SRCR Generator Wiring Diagram by following the path of AC power from stator (L4). This AC power from phase 1 and phase 2 passes through noise suppressor (FL1) through fuses (F1 and F2), wires (37 and 38) to the full wave bridge rectifier (CR1, CR2, CR3 and CR4) mounted on heat sinks (E1 and E2) which rectifies the AC power to provide full wave DC power. Center tap voltage surge suppression diode (CR7) across power rectifiers (CR3 and CR4) limits abnormal transient peak voltages on the bridge rectifiers. Fuses (F1 and F2) are the "fast blow" type and provide protection against secondary damage of the excitation circuit if any one component should fail or malfunction.The full wave DC power from the rectifiers continues from heat sink (E3) through regulator gain resistor (R1), wire (30), and noise suppressor (FL1) to the positive "+" end of revolving field (L3). To sustain current in revolving field (L3) when neither (CR1) or (CR2) is conducting (because of no circuit from stator phase 3) there is a circuit from the negative "-" end of the revolving field to the positive "+" end of the field. The circuit is from terminal (7) through noise suppressor (FL1) to terminal (8), through wire (29), field rectifier (CR5), regulator gain resistor (R1), through wire (30) to terminal (6) and through the noise suppressor to the positive end of the revolving field. This circuit maintains a