SEAL-O-RING 3D7805 - Caterpillar

All SRMP generators have the same basic design. SRMP generators have the following design characteristics:
Power for the exciter field is provided by the permanent magnet pilot excited (PMG) method .
The location of the bearing is inboard.
On PMG generators, the pilot exciter can be inboard or the pilot exciter can be outboard.Note: Some larger generators have two bearings. When a generator has two bearings, there is a bearing at each end of the generator shaft.
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PMG Type Components
(1) Rectifiers
(2) Pilot exciter field (permanent magnet)
(3) Pilot exciter armature (PM armature)
(4) Exciter armature (rotor)
(5) Exciter field (stator)
(6) Bearing with a sleeve for 3500 Engine Family only
(7) Main armature (stator)
(8) Main field (rotor)
(9) Rotor shaft
(10) Fan
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PMG Type Components with a Pilot Exciter
(1) Rectifiers
(2) Exciter field (stator)
(3) Exciter armature (rotor)
(4) Pilot exciter armature (PM armature)
(5) Pilot exciter field (permanent magnet)
(6) Bearing
(7) Main armature (stator)
(8) Main field (rotor)
(9) Rotor shaft
(10) Fan
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PMG Generator Wiring Diagram
(CR1 - CR6) Diodes
(CR7) Varistor
(L1) Exciter field (stator)
(L2) Exciter armature (rotor)
(L3) Main field (rotor)
(L4) Main armature (stator)
(L5) Pilot exciter armature
(PM) Permanent magnet
(R5) Resistor
(RFA) Rotating field assembly
(TR1) Optional Voltage droop transformer
(T0, T1, T2, T3, T7, T8, T9) Generator Terminals and/or Generator leadsRotating Field Assembly (RFA)
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RFA Components (PMG Type)
(1) Pilot exciter field (permanent magnet)
(2) Exciter armature (rotor)
(3) Bearing
(4) Main field (rotor)
(5) Rotor shaft
(6) RectifiersThe RFA components attach to rotor shaft (5), which is supported by the engine flywheel and bearing (3).Armature (Stator)
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Main Armature (Stator (L4))
The generator main armature is stationary and the generator main armature contains the stator windings.Main Field (Rotor)
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Rotating Field Assembly (RFA)
(1) Main Field (Rotor (L3))Generator Main Field (1) is part of the rotating field assembly. The generator main field rotates with the rotating field assembly.Exciter
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Exciter Armature (Rotor (L2))
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Exciter Field (Stator (L1))
Pilot Exciter
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Pilot Exciter
The pilot exciter is used on PMG generators. The pilot exciter consists of stationary pilot exciter armature (1) and the rotating pilot exciter field (2). 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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Three Diode Rectifier Block
(1) Positive rectifier block
(2) Negative rectifier block
Illustration 12 g00611973The rotating rectifier blocks are part of the rotating field assembly (RFA). There are three 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 three diode rectifier block contains three diodes. Two different blocks are required. One block is positive and the other block is negative.
The six diode rectifier block contains six diodes. One block is required.Note: For additional information, refer to Generator Operation, "Rectifier Circuits".