SOFTWARE GP- 3843720 - Caterpillar

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Exciter Field (Stator)Pilot Exciter
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Pilot Exciter Armature
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Pilot Exciter Field (Permanent Magnet (PM))A pilot exciter is used on permanent magnet pilot excited (PMPE) type generators. The pilot exciter consists of the stationary pilot exciter armature. Refer to Illustration 9. The pilot exciter also consists of the rotating pilot exciter field. Refer to Illustration 10. The pilot exciter field is also referred to as the permanent magnet (PM). Rotating Rectifier Blocks
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Two Diode Rectifier Block
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6 Diode Rectifier BlockThe rotating rectifier blocks are part of the rotating field assembly (RFA). There are two types of rotating rectifier blocks that are used. The size of the generator determines the size of the rotating rectifier block that is used.
The two diode rectifier block contains two diodes. Three identical blocks are required.
The six diode rectifier block contains six diodes. One block is required.Note: For additional information, refer to "Rectifier Circuits" within the Systems Operation Section, "Generator Operation". Note: Early SR4 generators were provided with six individual diodes. Three diodes on a positive heat sink, and three diodes on a negative heat sink.Voltage Regulators
VR3 Voltage Regulator
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Adjustment Controls of the VR3 Regulator (1) Voltage Droop Potentiometer (2) Voltage Level Potentiometer (3) Voltage Gain Potentiometer (4) Fuse(s) VR3F Voltage Regulator
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Adjustment Controls of the VR3F Regulator (1) Voltage Droop Potentiometer (2) Voltage Level Potentiometer (4) Fuse(s) VR4 Voltage Regulator
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Adjustment Controls of the VR4 Regulator (2) Voltage Level Potentiometer (3) Voltage Gain Potentiometer (4) Fuse(s)Digital Voltage Regulator (DVR)
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Digital Voltage Regulator (DVR) (5) Display (6) Function Key (7) Scroll Down Key (8) Scroll Up Key (9) Keypad (10) "J1" Connector (11) Screw Terminals
All Caterpillar SR4 generators, except the oilfield generators, are provided with voltage regulators. The voltage regulator controls the generator output voltage. Several types of voltage regulators are available. Refer to Illustrations 13, 14, 15, and 16.The VR3 regulators and all of the VR3F regulators have voltage droop adjustment (1). The VR4 regulator does not have a voltage droop adjustment. The VR4 regulator is not designed for parallel applications.The VR3, VR3F and VR4 regulators have voltage level control (2) .The VR3 and VR4 regulators have voltage gain adjustment (3). The VR3F regulator does not have a voltage gain adjustment.Voltage level and voltage gain are controlled by multiturn potentiometers. The adjusting screws on the potentiometers do not have a fixed stop. When the potentiometer reaches the end of adjustment, a ratchet action begins. The beginning of a ratchet action can be felt with the adjusting tool. The adjusting screw can be turned past the potentiometer stop (ratchet action) without further changing the potentiometer setting.The DVR is a microprocessor based voltage regulator. All the parameters are preset at the factory. The parameters can be modified in order to meet the specific requirements on the site. Certain system parameters can also be monitored on display (5) of the DVR. Keypad (9) is used to change the information that is shown on display (5). J1 connector (10) is used to join the DVR to a personal