Replace Exciter Rotor on LC6 Frame Generators{4457} Caterpillar

Generator Set:

3456 GEN SET (S/N: C1G1-1079; C3G1-701; C4G1-537; C2T1-292)

3406C GEN SET (S/N: C2G1-1523; C5G1-669; C8G1-251)

C18 GEN SET (S/N: G4C1-1267)

C9 GEN SET (S/N: C9E1-128)

Engine:

C15 (S/N: C5L1-125)

Electric Power Generation:

SR4B (S/N: G6B1-959)

Introduction

This Special Instruction will provide instructions for the replacement of the exciter rotor for the LC6 frame generators.

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Personal injury or death can result from high voltage. When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present. Improper test equipment can fail and present a high voltage shock hazard to its user. Make sure the testing equipment is designed for and correctly operated for high voltage and current tests being made. When servicing or repairing electric power generation equipment: Make sure the unit is off-line (disconnected from utility and/or other generators power service), and either locked out or tagged DO NOT OPERATE. Remove all fuses. Make sure the generator engine is stopped. Make sure all batteries are disconnected. Make sure all capacitors are discharged. Failure to do so could result in personal injury or death. Make sure residual voltage in the rotor, stator and the generator is discharged.

If the generator that is to be repaired is equipped with the permanent magnet generator (PMG) option, then refer to the "Remove PMG" section of this document first for information to remove the PMG.

LC6 Exciter Rotor Removal

1. Isolate the generator set before any work on the unit is begun. Activate all required emergency stops. Open the generator set breaker. Disconnect the battery cables. Ensure that all health and safety requirements are adhered to at all times.

2. Remove the generator exciter end bracket (36). Refer to Illustration 1.
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   Illustration 1	g01426073
   Alternator Break Down (1) Main Stator Assembly (4) Main Rotor Assembly (21) Lifting Ring (36) Exciter End Shield (37) Exciter End Shield Mounting Bolts (48) Top Cover (51) Air Intake Grill (70) Exciter End Bearing (71) Cover (72) Bearing Retainer Ring Mounting Bolts (78) Bearing Retainer Ring (79) Preload Washer (90) Exciter Stator (100) Exciter Rotor (343) Diode Bridge Assembly (347) Varistor (349) O Ring (365) Rear Cover (366) Side Cover (367) Side Cover

   1. Remove the air intake grill (51) .
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   Illustration 2	g01433670
   (51) Air Intake Grill

   2. Remove the lid of the protective cover (48). Remove the side panels (366) and (367) .
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   Illustration 3	g01433827
   (21) Lifting Hook (48) Top Cover (71) Cover on Exciter End Shield (365) Rear Cover (366) Side Cover

   3. Remove the hook (21). Remove the rear cover panel (365) .

   4. Install the hook (21) onto the exciter end bracket (36). The hook will allow a means to manipulate the bracket (36) during removal.

   5. Remove the main rotor shaft cover (71) that is on the exciter end shield.

   6. Disconnect the exciter wires (5+) and (6-) .
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   Illustration 4	g01434494
   Cable Straps Near AVR Terminal (36) Exciter End Shield (60) Cable Straps (67) Exciter Stator Leads

   7. A paper or cardboard type shim should be installed between the main rotor (4) and the main stator (1) windings in order to protect the stator and rotor windings.

   8. Attach a suitable lifting device to the hook (21) .

   9. Remove the two mounting bolts (72) for the bearing retainer ring (78) that assemble the retainer ring to the exciter end shield (36) .
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   Illustration 5	g01433910
   (36) Exciter End Shield (37) Exciter End Shield Mounting Bolt Locations (72) Bearing Retainer Ring Mounting Bolts

   10. Install the bolt (10) that came with the repair kit into the end of the main rotor shaft (11) .

   11. Remove the five mounting bolts (37) of the exciter end shield.
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   Illustration 6	g01433911
   (1) Main Stator Assembly (10) Bolt (11) Exciter End of Main Rotor Shaft (12) Prybar (36) Exciter End Shield

   12. Position a prybar (12) as shown in Illustration 6. Carefully pry the shield loose. Be sure to reposition the prybar around the shield in order to pry the shield off evenly.

   13. Carefully remove the exciter end shield (36) .

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Illustration 7	g01434151
Exciter End Shield Removed (36) Exciter End Shield (90) Exciter Stator

3. Remove the Preload Washer (79) and the O Ring (349) .

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Illustration 8	g01434546
Exciter End Shield and Stator Removed

4. Remove the bolt (10) that was installed into the end of the main rotor shaft.

5. Disconnect the main rotor leads (61) to the exciter rotor diode assembly (62). Refer to Illustration 9.

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Illustration 9	g01434499

6. Assemble a central screw type of puller to the bearing (70) that is on the exciter end of the main rotor (4) .

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Illustration 10	g01426077
Installed Bearing Puller (70) Exciter End Bearing (100) Exciter Rotor

7. Remove the exciter end bearing (70) and bearing retainer ring (78) .

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Illustration 11	g01434541

8. Remove the exciter rotor (100). Use a puller that is similar to the one that is shown in Illustration 12.

Illustration 12	g01434686
(4) Main Rotor Shaft (100) Exciter Rotor

New Exciter Rotor Installation

1. Place the new exciter rotor on the main rotor shaft. Assemble an installation tool that is similar to the one that is shown in Illustration 13 to the exciter and to the main rotor shaft.

2. Press the new exciter rotor into position by tightening hexagon nut (6) of the installation tool assembly (9). Refer to Illustration 13 and Illustration 14.

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Illustration 13	g01426087
Exciter Rotor Installation Tool Assembled on the Main Rotor (4) Main Rotor Shaft (5) Washer (6) Nut (7) Threaded Rod (8) Exciter Rotor (9) Installation Tool Assembly

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Illustration 14	g01426089
Installation Tool Dimensions are in Metric Centimeters.

3. Connect the main rotor field leads to exciter rotor diode assembly.

4. Assemble the bearing retainer ring (78) to the main rotor shaft.

5. Heat the new bearing first in order to assemble the bearing to the main rotor shaft. Install the bearing.

6. Install the new O ring and thrust washer. Install the generator exciter end shield.

7. Screw a threaded rod (110) into the bearing retainer ring (78).

8. Screw the threaded dowel (111) in to the end of the main rotor shaft.

9. Install the exciter end shield (36). Assemble the flat plate (112) to the threaded dowel (111). Assemble the nut (113) to the threaded dowel (111). Tighten the nut (113) in order to press the exciter end shield into position. Refer to Illustration 15.

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Illustration 15	g01426093

10. Assemble the exciter end shield mounting bolts to the shield. Torque the bolts to the appropriate specifications.

11. Install one of the bearing retainer ring mounting bolts (72). Remove the threaded rod (110) from the bearing retainer ring. Install the other bearing retainer ring mounting bolt (72). Torque the bolts to the appropriate specifications.

12. Remove the nut (113), the flat plate (112), and the threaded dowel (111) .

13. Install any covers or other generator components that were removed.

14. Clear the generator area, reconnect the batteries cables, and release any active emergency stop that was set due to the generator set service procedure. Clear the emergency fault code.

15. Run a functional "No load test" on the generator set.

PMG Option Removal

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Illustration 16	g01434782

1. Remove the four mounting bolts for the PMG end plate (297) .

2. Remove the mounting bolts (294) that assemble the PMG stator to the PMG housing (290). Disconnect wiring and remove PMG stator (293) .

3. Remove the tie rod (295) nut and the gland washer (296) .

4. Remove the magnetic rotor (292) and the shaft adapter (291) .

5. Remove the mounting bolts for the PMG housing (290) .

PMG Option Installation

1. Install for the PMG housing (290) to the exciter end shield.

2. Apply some anti-vibration adhesive to the threads of the tie rod (295). Install the tie (295). Torque the tie rod to 30 N·m (22 lb ft).

3. Assemble the shaft adapter (291) to the magnetic rotor (292). Install two M10 threaded rods into the magnetic rotor. Use the threaded rods in order to assemble the magnetic rotor (292) onto the tie rod (295) .

4. Once the magnetic rotor is in the correct position, remove the two M10 threaded rods.

5. Install the cable gland washer (296). Secure the gland washer with the gland washer nut.

6. Install the PMG stator (293) .

7. Install the PMG cover (297) .

8. Connect wiring.