- Engine:
- C15 (S/N: C5E1-UP; C5L1-UP)
- Generator Set:
- 3406C GEN SET (S/N: C2G1-UP; C5G1-UP; C8G1-UP)
- 3456 GEN SET (S/N: C1G1-UP; C3G1-UP; C4G1-UP; C2T1-UP)
- C15 GEN SET (S/N: C5H1-UP)
- C18 GEN SET (S/N: C6C1-UP; G4C1-UP; STD1-UP; STM1-UP; EKW1-UP)
- C9 GEN SET (S/N: C9E1-UP)
- 3456 GEN SET (S/N: C1G1-UP; C3G1-UP; C4G1-UP; C2T1-UP)
- Industrial Engine:
- C15 IND (S/N: JRE1-UP)
Introduction
The ""Problem" " that is identified below does not have a known permanent solution. Until a permanent solution is known, use the ""Solution" " that is identified below.
The following items are affected by this Technical Information Bulletin:
Problem
The Caterpillar R448 Voltage Regulator may fail to operate properly if the following criteria are not met:
- The generator and the voltage regulation system is not correctly adjusted.
- The generator and the voltage regulation system is not correctly set up.
- The generator and the voltage regulation system is not correctly maintained.
Additionally, the following issues have been identified:
- Some Voltage Regulator failures are reported against the incorrect part number for the Voltage Regulator.
- Some reports of failures may be caused by the incorrect setup of the voltage regulator.
- If the dealer or the customer has replaced the Voltage Regulator in the field, the regulator may not have been set up correctly for matching the default characteristics of the generator.
- The Voltage Regulator may be diagnosed incorrectly as the cause of the fault. The actual cause of the fault could be one of the following items in the following list:
- The main stator
- The main rotor
- The exciter stator
- The exciter rotor
Solution
Correct Part Number Identification And Replacement
The Voltage Regulator has been redesigned. The 289-4769 Voltage Regulator As replaces the former 242-3958 Voltage Regulator Gp . Use only the 289-4769 Voltage Regulator As for feild repairs.
If the former Voltage Regulator 242-3958 Voltage Regulator Gp fails in field, the same part number ( 242-3958 Voltage Regulator Gp ) must be recorded on warranty claims. The new part number for the Voltage Regulator 289-4769 Voltage Regulator As should only be entered on warranty claims if the 289-4769 Voltage Regulator As has actually failed. The new part number for the Voltage Regulator ( 289-4769 Voltage Regulator As ) pertains to the following products:
- APS (China) built product
- The following Larne (UK) built generators serial numbers: (S/N: L5A00749-UP), (S/N: L6B3402-UP) and (S/N: L7A639-UP).
- The following Griffin (USA) built generators serial numbers: (S/N: G7A302-UP), (S/N: G6B1871-UP) and (S/N: G5A575-UP).
Identification of the correct part number for the Voltage Regulator for warranty claims can be made visually as follows:
 | |
| Illustration 1 | g01451579 |
The former 242-3958 Voltage Regulator Gp has bare link wires (1) protruding from the black potting resin. Refer to Illustration 1.
 | |
| Illustration 2 | g01451577 |
The new 289-4769 Voltage Regulator As has links (2) that are covered with white PVC protruding from the potting resin. Refer to Illustration 2.
Setup Of The Voltage Regulator
Refer to the ""Reference" " Section for a list of manuals that contain the following information:
- Setup procedures for the Voltage Regulator
- Jumper information for the Voltage Regulator
- Adjusting potentiometer identification
- Set up information
- Additional information
None of the incorrectly set up jumpers should cause the Voltage Regulator failure. However, poor generator performance may appear as a Voltage Regulator failure. Table 1 identifies how the incorrect jumper settings on the 289-4769 Voltage Regulator As and the 242-3958 Voltage Regulator Gp may affect the generator performance. Refer to Illustration 3 for the position of the jumpers on 289-4769 Voltage Regulator As .
Refer to Table 1 for the differences between the setups of 242-3958 Voltage Regulator Gp and 289-4769 Voltage Regulator As .
 | |
| Illustration 3 | g01451634 |
| Jumper or Pot | Function | Link | Configuration |
Voltage Regulator Functionality Notes | ||
|---|---|---|---|---|---|---|
| Cut | Uncut | |||||
| ST1 | Sensing Detection | X | Three-phase sensing |
Link cut with only R448 fitted will cause shutdown. This failure may appear as loss of sensing. |
||
| X | Single Phase sensing |
|||||
| ST2 | Response Time | X | Fast |
Incorrect selection will cause poor performance. | ||
| X | Normal |
|||||
| ST3 | Frequency Setup |
Terminal Jumper | 50 Hz Position (1). |
The wrong selection will cause instability of the generator voltage. | ||
| 60 Hz Position |
||||||
| ST4 | External Voltage Potentiometer | Terminal Jumper | Removed | Remote Pot, or Three-Phase Sensing | The wrong configuration will prevent the full range of voltage adjustment, or may cause performance issues. (2) | |
| Installed | No Remote Pot Used | |||||
| ST5 | Load Adjustment Module | Miniature 2-pin Jumper |
Removed | Load Adjustment Module Off | Incorrect selection will disable Load Adjustment Module. Transient performance may be improved with the Load Adjustment Module on. | |
| Installed | Load Adjustment Module On | |||||
| ST6 | Generator Frame | X | 7000 Frame | Incorrect selection will cause will cause poor performance. | ||
| X | 5000 and 6100 Frames | |||||
| ST9 | Exciter Type | X | Permanent Magnet | Incorrect selection will cause poor performance. An uncut link will not provide the 300 percent overcurrent for up to 10 seconds on generators that are equipped with Permanent Magnets. | ||
| X | Auxiliary winding Regulation Excitation Principle, Shunt or Self-Excited | |||||
| ST10 | Load Adjustment Module Voltage Level | Miniature 3-Pin Jumper |
13 percent (3) | Incorrect selection may cause poor performance. (4) | ||
| 25 percent (5) | ||||||
| ST11 | Frequency Knee | X | 65 Hz | Incorrect selection will cause poor performance. Caterpillar generator sets do not utilize the 65 Hz option. (5) | ||
| X | 48/58 Hz | |||||
| P1 | Voltage Quad. Droop | Built-in Potentiometer | Adjusts the reactive droop in paralleling operation | Zero droop is set when the pot fully counterclockwise. | ||
| P2 | Voltage | Built-in Potentiometer | Adjusts the general terminal voltage. | The minimum voltage is set when the pot is fully counterclockwise. | ||
| P3 | Stability | Built-in Potentiometer | Adjusts the response to transient changes | Adjust from mid-position (adjust in both directions). You may need to cut ST2, if required. | ||
| P4 | Threshold/LAM or U/F | Built-in Potentiometer | Adjusts the Underspeed protection and "LAM" trip threshold | Maximum frequency fully counterclockwise. If ST3 = 50 Hz then (factory) = 48 Hz. If ST3 = 60 Hz then (factory) = 58 Hz. (6) | ||
| P5 | Excitation Current Ceiling | Built-in Potentiometer | Adjusts the maximum excitation current limit. | Minimum (4.5 Amperes) limit set when pot fully counterclockwise, maximum (10 Amperes) when fully clockwise. Low setting may cause Voltage Regulator fault (current drop to 1 Ampere) and require restarting the generator set. (7) | ||
| ( 1 ) | Refer to Illustration 3. |
| ( 2 ) | When the optional 246-5894 Sensing Module As is equipped with the R448 Automatic Voltage Regulator, the voltage stability can be improved by installing the ST4 jumper. |
| ( 3 ) | Place the jumper on the farthest pins from the heat sink. |
| ( 4 ) | Only available on 289-4769 Voltage Regulator As |
| ( 5 ) | Place the jumper on the closest pins to the heat sink. |
| ( 6 ) | P4 is only available on the 242-3958 Voltage Regulator Gp . P4 is located midway between P3 and P5. |
| ( 7 ) | The overexcitation fault can be determined by observing the green LED on the Voltage Regulator. While the generator is operating, the LED should be constantly illuminated. If the LED is not illuminated, this indicates a fault condition. |
Troubleshooting And Maintenance
Setup
Check the jumper and check the pot settings as shown in Table 1.
Three-Phase Sensing
One of the following conditions may occur if an unbalanced load is present:
- Overvoltage
- Undervoltage
- Voltage fluctuation
Consider installing the 246-5894 Sensing Module As .
Terminals
Check the terminals in order to ensure that one or more of the following conditions have not occurred:
- The terminals are damaged.
- The terminals are too close to each other.
- The terminals are touching each other.
Note: Make sure that the terminals are clean. Make sure that there is not dirt and/or dust around the connectors.
Insulation Deterioration
The insulation on one or more of the following windings may deteriorate: the main stator, the main rotor, the exciter stator and the exciter rotor. Thus, the insulation resistance becomes unacceptable for proper operation and safe operation. While severe deterioration may result in burnout of the windings, less severe results can result in one or more of the following conditions: undervoltage, overvoltage and Voltage Regulator shutdown. These conditions may occur after 10 seconds from start-up. These conditions can especially occur when moisture and/or condensation affects the winding insulation. This may not be apparent as a cause of failure, since the windings are not visible and condensation and/or moisture may have evaporated by the time the service technician troubleshoots the generator set. Check the following steps:
- Perform an insulation test on the main stator windings. If the results indicate an unacceptable insulation resistance, repair the windings or replace the windings.
Additional information about performing an insulation test on the main stator windings can be found in the manuals that are listed in the ""Reference" " Section.
AVR failures can be caused by the failing generator windings. The most effective method to prevent this is to conduct periodic insulation tests of the main stator windings. If in doubt on how to perform insulation tests, use the following simple means in order to perform and evaluate the insulation tests.
The following steps are the recommended insulation test on the main stator:
- Do not proceed any further until you lock out the generator set.
- Disconnect the power leads from the generator terminals.
- Disconnect all control wiring from the generator terminals.
- Connect one megohmmeter lead to the wye connection and the other lead to the ground.
- Set the tester voltage to 500 Vdc for generators that are 600 volts or less. Set the tester voltage to 1000 Vdc for generators over 600 volts.
- Apply the test voltage and record the readings at the following intervals: 30 seconds, 60 seconds and 10 minutes.
Note: The value of resistance that was measured for 30 seconds must be greater than 1.0 megohm. Refer to Special Instruction, SEHS9124, "Cleaning and Drying of Electric Set Generators".
Show/hide table
Personal injury or death can result from electrocution.
The megohmmeter is applying a high voltage to the circuit.
To avoid electrocution, do not touch the instrument leads without first discharging them. When finished testing also discharge the generator windings.
- Evaluate the results by calculating the Polarization Index. This is accomplished by dividing the 10 minute reading by the 1 minute reading.
Refer to Table 2 for the required actions.
Show/hide tableTable 2 Polarization Index Winding State Action Less than 1.5 Poor/Failing Clean the generator set and dry the generator set. Refer to Special Instruction, SEHS9124, "Cleaning and Drying of Electric Set Generators". Between 1.5 and 2.0 Marginal Increase the monitoring frequency to monthly. Over 2.0 Good Maintain the recommended tests per the Operation and Maintenace Manual of the Product.
- Measure the resistance of the exciter stator windings. If the measurements are outside the values that are listed below, the exciter stator is faulty. Repair the windings or replace the windings. Refer to the following measurements:
5000 Series (Generator Serial Number (S/N: L5B; G5B) ) ... 8.5 ohms to 10.6 ohms
6100 Series (Generator Serial Number (S/N: L6B; G5B) ) ... 9.0 ohms to 11.0 ohms
7000 Series (Generator Serial Number (S/N: L7B; G5B) ) ... 10.8 ohms to 13.2 ohms
Moisture
Always make sure that the generator and the controls have been thoroughly dried before you place the items into service. A standard generator set control panel and generator connection box is designed to prevent rain water ingress. However, when the generator set is subjected to pressure washing during the routine maintenance, there is the danger that water may enter the terminal box. This is especially true if the water stream is applied at directions other than from directly above the generator. The subsequent operation of the generator may lead to failures of the Voltage Regulator.
Loss of Magnetism
In certain situations the generator residual magnetism may be lost. Field flashing is recommended in this case. However, to avoid permanently damaging the Voltage Regulator, it is essential that the battery power polarity that is used for the field flashing is correct. The positive side of the battery must be connected to E+. The negative side of the battery must be connected to E-.
Proper Connections
The generator set must not be started or the generator set must not be run under the following conditions:
- Wire E+ and wire E- are not connected to the Voltage Regulator.
- Available power inputs (X1, X2, Z1, Z2) are connected to the Voltage Regulator.
Additional Troubleshooting Information
| Fault | Action | Effect | Check/Cause | |
| No voltage at no load on start up. | Flash the exciter stator: Using either a 6 Vdc battery or a 12 Vdc battery, connect battery positive to E+ and battery negative to E- for 2 to 3 seconds when the engine is stopped. Then restart generator set. | When restarted, the alternator builds up its correct voltage. | Problem was lack of residual magnetism, for Self-excited or AREP generators. | |
| When restarted, the alternator provides no voltage or does not reach the rated voltage. | Check the power connections X1, X2, Z1, Z2 to the AVR Check exciter stator wiring/resistance Check main rotor resistance Check diodes Check armature (main stator) for short-circuit |
|||
| Voltage too low | Adjust the voltage potentiometer (P2) or the remote voltage adjust potentiometer. Stop the generator set. Restart the generator set. Check the voltage again. |
When the generator set is restarted, the rated voltage should be present. | Check that the sensing wires are connected to the correct terminals (0V, 110, 220, 380) Check main rotor resistance Check exciter rotor resistance Check diodes AVR may be faulty Overload may have caused AVR short-circuit protection shutdown to activate temporarily. |
|
| Voltage too high | Adjust the voltage potentiometer (P2) or remote voltage adjust potentiometer. | The rated voltage should be present. | Check that the sensing wires are connected to the correct terminals (0V, 110V, 220V, 380V) AVR may be faulty |
|
| Voltage fluctuations or oscillations | Adjust AVR stability potentiometer | If no effect, try normal/fast recovery modes (ST2) | Check the engine speed for possibility of speed fluctuations on no load Check for loose connections to the AVR Speed too low when on load (or U/F bend set too high) Check if load may affect alternator performance, especially electronic equipment (computers, thyristor controlled lamps or motors etc.) AVR may be faulty |
|
| Voltage correct at no load and too low when on load (1) | Run at no load and check the voltage between E+ and E- on the AVR | Voltage between E+ and E- | SHUNT is less than 20 V | Check ST11 is not cut |
| AREP or PMG is less than 10V | ||||
| Voltage between E+ and E- | SHUNT is less than 30V | Check diodes Check main rotor resistance Check exciter stator wiring/resistance |
||
| AREP or PMG is less than 15V | ||||
| Voltage disappears during operation. (2) | Check the AVR, the surge suppressor, the rotating diodes, and replace any defective components | The voltage does not return to the rated value. | Check exciter stator wiring/resistance Check exciter rotor resistance Check main rotor resistance AVR may be faulty |
|
| ( 1 ) | For single-phase operation, make sure that the sensing wires coming from the AVR are correctly connected to the operating terminals |
| ( 2 ) | This may also be caused by the AVR internal protection being activated due to one AVR overload, open circuit, short-circuit. |
Reference
- Operation and Maintenance Manual, SEBU7777, "C9 Marine Generator Set"
- Operation and Maintenance Manual, SEBU8331, "C18 Power Module"
- Operation and Maintenance Manual, SEBU8134, "C3.3 and C4.4 Generator Sets"
- Operation and Maintenance Manual, SEBU7898, "C18 Generator Sets"
- Operation and Maintenance Manual, SEBU7909, "C15 Generator Sets"
- Operation and Maintenance Manual, SEBU8139, "C6.6 Generator Set"
- Operation and Maintenance Manual, SEBU7878, "C9 Generator Set"
- Operation and Maintenance Manual, SEBU7829, "3456 Generator Sets"
- Operation and Maintenance Manual, SEBU7828, "3406C Generator Sets"
- Operation and Maintenance Manual, SEBU8136, "C1.5 and C2.2 Generator Sets"
- Operation and Maintenance Manual, SEBU7843, "3408C and 3412C Marine Generator Sets"
- Operation and Maintenance Manual, SEBU7842, "3406C Marine Generator Sets"
- Bound Book, LEBQ4823, "A Stitch In Time - The Complete Guide to Electrical Insulaltion Testing"