Start By:
- Remove access cover and diode assembly. Refer to Disassembly and Assembly, KENR8990, "Diode Assembly - Remove and Install" section of this publication.
- Remove the PMG components. Refer to the Disassembly and Assembly, KENR8990, "PMG Removal Procedure" section of this publication.
- Remove the end bracket. Refer to Disassembly and Assembly, KENR8990, "End Bracket - Remove" and "End Bracket - Install".
- Remove the four exciter stator mounting bolts (25).
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Illustration 2 g01662994 (21) Exciter stator
(23) Bearing retainer bar
(25) Exciter stator mounting bolts - Attach a suitable lifting device (26) to exciter stator (21). Remove the exciter stator. The weight of exciter stator (21) is approximately
82 kg (180 lb) .
Note: Make an alignment mark (20) from the end bracket to the exciter stator (21) for installation purposes.
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| Illustration 1 | g01663013 |
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(20) Alignment mark
(21) Exciter stator (22) End bracket | |
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| Illustration 3 | g01662996 |
There are three different types of exciter rotors used for the 3000 frame generators:
- Shrink fit (not for reuse)
- Taper lock (The taper lock is intended to replace the shrink fit rotor.)
- Rotor lock nut
The shrink fit exciter rotor is a one time use component. The shrink fit exciter rotor will lose the interference fit when removed. When a shrink fit exciter rotor must be replaced, the replacement for the shrink fit exciter rotor is a taper lock exciter rotor. The original shrink fit design has a laminate steel core that is a press fit directly on the main generator rotor shaft.
The original shrink fit design will require the use of a large puller to remove the exciter rotor. The use of heat may be necessary to remove the original shrink fit rotor.
Note: Do not attempt to reuse or rewind the original shrink fit rotor. The interference fit between the laminate steel and the main rotor will be damaged with removal.
Another type of exciter rotor is a taper lock exciter rotor. A taper lock exciter can be identified by observing that the exciter uses cap lock mounting bolts between the inner cone and outer section of the exciter.
The third type of exciter rotor is the rotor lock nut exciter rotor. The rotor lock nut exciter rotor uses a lock nut mounting design. Refer to Illustration 20. The rotor lock nut exciter rotor should be replaced the same lock nut design for proper clearance.
Note: Lock nut exciter rotors have different part numbers than the older shrink fit designs. Refer to the parts manual or "Service Information System" web site to identify the correct part that is needed.
| Required Tools | |
|---|---|
| Qty | Description |
| 1 | Adapter |
| 1 | Driver Gp |
| 1 | Three Jaw Puller |
Remove access cover and diode assembly. Refer to Disassembly and Assembly, KENR8990, "Diode Assembly - Remove and Install" section of this publication.
Remove the PMG components. Refer to the Disassembly and Assembly, KENR8990, "PMG Removal Procedure" section of this publication.
Remove the end bracket. Refer to Disassembly and Assembly, KENR8990, "End Bracket - Remove" and "End Bracket - Install".
Remove the rear bearing. Refer to Disassembly and Assembly, KENR8990, "Bearing - Remove and Install (Rear Bearing - Remove and Install)".
Bearing and Exciter Rotor Removal with a Puller
- Cut the leads and the lacing that secures the exciter rotor leads where the leads enter the main rotor shaft.
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Illustration 5 g03386827 (27) Exciter rotor lead lacing partially removed
(28) Exciter rotor leads cut - Remove the exciter rotor leads by pulling the wires from the end of the main rotor shaft. Refer to Illustration 6.
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Illustration 6 g03386813 (30) Exciter leads cut and removed. - Loosen the clamp (31) that secures the two main rotor leads (32) where the leads go through the main rotor shaft (33).
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Illustration 7 g03386904 Main rotor leads moved to avoid damage or disassembly interference.
(31) Clamp
(32) Main rotor leads access hole location
(33) Main rotor shaft leads pushed back into access hole - Pull the rotor leads out of the main rotor shaft enough to avoid interference with the puller. If the leads are not pulled out, lead damage during the puller tool installation can occur.
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Illustration 8 g03386909 Typical example of a bearing puller installed - Install the three jaw puller tool and remove the rear bearing. Refer to Disassembly and Assembly, KENR8990, "Bearing - Remove and Install (Rear Bearing - Remove and Install)".
- The bearing that was removed is to be discarded and a new bearing is to be used for the reassembly.
Note: Prior to installation, the new bearing, the bearing temperature must be raised to approximately
107° C (225° F) . - Install the three jaw puller tool and remove the exciter rotor.
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Illustration 9 g03386911 (35) Proper puller jaw location - Make sure that the tip of the puller is grabbing the exciter rotor core and not the end turns.
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| Illustration 4 | g03386817 |
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Typical example of generator with the end bracket removed and exciter rotor exposed. | |
Note: Removing the shrink fit exciter rotor from the main rotor shaft can be difficult, even with a 10,000 psi pump.
If the exciter rotor cannot be removed using the steps above, a torch will be required to heat the exciter rotor.
Exciter Rotor Removal Using a Torch
- Ensure that the puller has appropriated pressure on the exciter rotor. Ensure that the main rotor windings and stator windings are appropriately protected from heat.
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Illustration 10 g03386935 Typical process of heating the exciter rotor enough to be removed. - The use of a rose-bud torch is suggested. Evenly heat the exciter rotor. Maintain a constant pressure on the exciter rotor with the hydraulic press.
- Once the exciter rotor begins to move, maintain pressure on the rotor until the rotor is free of the main rotor shaft.
Note: Ensure that proper precautions are used to protect people in the work. The parts will be hot.
- Use a suitable lift to finish removing the exciter rotor.
- Attach a suitable lifting device (26) to exciter stator (21). The weight of exciter stator is approximately
82 kg (180 lb) .Show/hide table
Illustration 12 g01663076 - Position the exciter stator (21). Install the four exciter mounting bolts (27 25).
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| Illustration 11 | g01662996 |
Taper Lock Exciter Rotor Removal and Installation
| NOTICE |
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Bolt removal requires strict procedures. The bolts must be loosened gradually in a specific pattern. If a few of the bolts are fully loosened, the remaining bolts will carry the entire load and therefore will be difficult to remove. Installations in extreme conditions may cause the bolt tip to deform, making bolt removal difficult. |
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| Illustration 13 | g03445436 |
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Typical example of the taper lock hub installed for the exciter rotor (37) Taper lock hub installed | |
Removal of the taper lock requires removing all the 14 inner cap bolts. Use 7 of the inner cap bolts in the jacking screw locations to separate the sections of the taper lock and remove. Refer to Illustration 14 and the following steps for a more in-depth explanation. The taper lock rotor can be replaced with the same exciter design. If no damage is evident to the original exciter, the taper lock exciter can be rewound at a capable rewind shop and used again. Refer to the following instructions and Illustrations 14 through 18.
- Loosen each mounting bolt (38) 1/4 of a turn following a circular pattern around the tensioner. As you move around and get back to the first bolt, the first bolt will be tight again. Repeat for all bolts prior to the next step. Refer to Illustration 14.
Note: If time permits, spray bolts with a penetrating oil or hydraulic oil prior to starting, especially if components show signs of rust.
- Repeat the bolt loosening sequence again for all the bolts.
- Repeat the bolt loosening sequence again for all the bolts.
Note: Do not use an air impact for the first three times that the bolts are loosened. For long bolts, more than three rounds may be required before using impact tools.
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| Illustration 14 | g03385127 |
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Pattern for tightening and loosing bolts (38) Mounting bolts (39) Jack bolt holes | |
- Install the taper lock removal bolts (38) into all the jackscrew holes (39). Hand tighten only. Refer to Illustration 14.
- Tighten the taper lock removal bolts (38) by turning the bolts 1/4 turn, following a similar sequence to the installation procedure.
- Repeat these steps until the inner sleeve is loosened from the exciter rotor assembly
- Gather the parts and supplies that will be needed. Some of the supplies include AW 32 type oil, cleaner, clean rags or paper towels, and wrenches.
- Remove all machine oil and dirt. Clean all contact surfaces with cleaner.
- Lubricate the thread portion of the bolts used for taper lock removal.
- Slide hardened washers onto bolts.
- Lubricate the washer with the appropriate lubricant.
Clean the shaft step with cleaner to ensure that there is no oil or dirt. Allow to dry prior to sliding exciter rotor assembly.
Taper Lock Exciter Rotor Assembly
Make sure that there is no debris, chips, or dirt in the tapped holes of the taper lock sleeve. Clean the contact surfaces with cleaner to remove any oil or dirt. Allow surfaces to dry prior to assembly or applying oil to tapered surface. If the inner sleeve will be installed after sliding the rotor assembly on, do not apply oil to tapered surface. Oil applied to the tapered surface could allow the shaft step to come in contact with oil which could allow slippage between locking surfaces.
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| Illustration 15 | g03386936 |
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Typical example of an exciter rotor. (40) Slot for tab ring (if a tab ring is used) | |
Make sure that there is no debris, chips, or dirt in the threaded holes. Clean contact surfaces with cleaner to remove all potential oil or dirt. Allow surfaces to dry prior to assembly or applying oil to tapered surface. Lightly oil with a clean rag or paper towel to only the tapered surfaces prior to installation on the rotor shaft. A screw driver or pry bar may be used to spread the inner sleeve enough to install the sleeve easily onto the rotor shaft step.
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| Illustration 16 | g03387349 |
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Typical example of a taper lock bushing | |
Ensure that the exciter rotor and inner sleeve is pushed up all the way against the step of the rotor shaft. During the tightening sequence, the exciter rotor will have a small gap or separation from the step which is normal. There can be no gap between the inner sleeve and the step in the rotor shaft. If a gap occurs, follow the loosening sequence then reposition the sleeve. Ensure that the sleeve is in contact with the step that is in the rotor shaft. Refer to Illustration 14.
An appropriate information source must be used to determine the bolt torque for the hardware size and type. As a reference, the nominal 100% torque for a M10 size fastener, Class 10.9 is
Perform the following instructions to install the exciter rotor.
- Install two protective sleeves that are each 6 inches long. Place one sleeve over the exciter rotor wires where the wires enter the generator rotor shaft. Place the other sleeve over the exciter rotor wires where the wires exit the generator rotor shaft. Refer to Illustration 17.
- Lacing cord and varnish will be needed to secure the exciter rotor leads to the main rotor.
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Illustration 18 g03386965 Exciter rotor installation
(45) Exciter rotor installed on main rotor
(46) Taper lock bushing being installed into position - Install exciter rotor and tapered bushing. Refer to Illustration 18.
- Refer to Illustration 14 for the bolt tightening sequence.
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| Illustration 17 | g03386958 |
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Typical example of the protective sleeves installed on the exciter rotor leads. (41) Protective sleeve on exciter rotor leads near the rotor (42) Main rotor access hole with properly located protective sleeve on exciter rotor leads (43) Main rotor (44) Properly positioned sleeve for exciter rotor leads | |
- Spin the bolt down on to the main thread until the bolt seats against the washer. Back the bolt off to create a 1/16" to 1/8" gap between the bolt head and washer.
- At about 30% or about
16 N·m (12 lb ft) of the target torque, tighten the bolts in crisscross pattern sequence. Refer to Illustration 14. - Recheck the torque for all 18 screws. Ensure that all screws are at 30% of the target value before proceeding.
- At about 60%, or approximately
33 N·m (24 lb ft) of the target torque, tighten the bolts in crisscross pattern sequence shown in 14. - Recheck torque of all 18 screws, assuring that all screws are at 60% of the target value before proceeding.
- At about 100%, or approximately
54 N·m (40 lb ft) of the target torque, tighten bolts in crisscross pattern sequence shown in 14. - Recheck torque at all 18 screws, assuring that all screws are at 100% of the target value before proceeding.
- At the target torque, tighten all bolts in a circular pattern.
- Repeat Step 8 until all the bolts are "stabilized", which means there is less than a 10 degree rotation. The process may require 2 to 4 additional passes.
- Install a new bearing. The bearing temperature must be raised to approximately
107° C (225° F) . Refer to Disassembly and Assembly, KENR8990, "Bearing - Remove and Install" for information about rear bearing removal and installation if needed. - Install the end bracket. Refer to Disassembly and Assembly, KENR8990, "End Bracket - Remove" and "End Bracket - Install" for installation information.
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Illustration 19 g03387052 Rotating rectifier and exciter wiring installation - Install the PMG and rotating rectifier assemblies.
- Cut the exciter rotor leads to the right length and install the wire terminals.
End By:
- Complete the assembly of the unit. Once the repairs are completed, check package vibration to make sure that the unit is operating within Caterpillar specifications.
- Use suitable tools to bend the flange on the tab ring away from the lock nut.
- Use suitable tools to unscrew the lock nut from the rotor.
- Remove the tab ring.
- Remove the exciter. Refer to Systems Operation/Test and Adjust/Disassembly and Assembly, KENR8990, "Exciter Remove and Install" section for information to remove the exciter. The information is located in the sub sections titled "Bearing and Exciter Rotor Removal with a Puller" or "Exciter Rotor Removal Using a Torch".
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| Illustration 20 | g03385193 |
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(50) Lock nut
(51) Tab ring (52) Exciter slot for tab ring locator (53) Tab ring locator | |
- Ensure that the rotor shaft has been properly prepared for installation of the new exciter. Refer to Illustration 21.
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Illustration 22 g03533816 (51) Tab ring installed against new exciter rotor. - After the exciter is installed, install the tab ring.
Note: Ensure that the tab ring is seated against the exciter.
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Illustration 23 g03385198 (50) Lock nut partially installed
(51) Installed tab ring - Start the lock nut by hand. Refer to Illustration 23.
- Use appropriate tools to secure the lock nut against the tab ring.
- After the lock nut is in the appropriate location, bend one of the tabs on the tab ring into one of the slots of the lock nut.
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| Illustration 21 | g03533820 |
