- Engine:
- 3306B (S/N: B8D1-UP; 8NS1-UP)
- 3408C (S/N: TAM1-UP)
- 3412 (S/N: 2WJ1-UP; 4BZ1-UP)
- 3412C (S/N: 5FL1-UP; DJN1-UP; 9EP1-UP; RLR1-UP; TFT1-UP; BCW1-UP; LRY1-UP)
- 3412E (S/N: TGC1-UP)
- 3508 (S/N: CNF1-UP; 70Z1-UP)
- 3508B (S/N: CNB1-UP; S2B1-UP; 3DM1-UP)
- 3512 (S/N: CMJ1-UP; 67Z1-UP)
- 3512B (S/N: CMC1-UP; S2H1-UP)
- 3516 (S/N: CMD1-UP)
- 3516B (S/N: BPJ1-UP; FDN1-UP; 7RN1-UP; PBR1-UP; S2R1-UP; GZS1-UP; PPS1-UP)
- G3306 (S/N: JCA1-UP)
- G3406 (S/N: R7E1-UP; KAR1-UP)
- G3408 (S/N: 6NB1-UP; 6RJ1-UP)
- G3408C (S/N: BAZ1-UP)
- G3412 (S/N: R7A1-UP; 7DB1-UP; KAP1-UP)
- G3516 (S/N: ZBA1-UP; 4EK1-UP; CSZ1-UP)
- G3516B (S/N: ZBC1-UP)
- G3520C (S/N: CWY1-UP)
- 3408C (S/N: TAM1-UP)
- Generator Set:
- 3406C GEN SET (S/N: C2G1-UP; KPS1-UP; 9ES1-UP; LRX1-UP)
- 3406C MARINE GS (S/N: PFH1-UP)
- 3406E GEN SET (S/N: 8AZ1-UP)
- 3412 GEN SET (S/N: 81Z1-UP; B3G1-UP; 25Z1-UP)
- 3456 GEN SET (S/N: CCB1-UP; CAH1-UP; GHJ1-UP; CBX1-UP)
- 3406C MARINE GS (S/N: PFH1-UP)
- Industrial Engine:
- C-15 IND (S/N: BEM1-UP)
- Marine Engine:
- C18 MARINE (S/N: C1J1-UP)
- Power Module:
- PM3412 (S/N: CAJ1-UP)
- PM3508 (S/N: BLM1-UP)
- PM3512 (S/N: BRF1-UP)
- PM3516 (S/N: BPD1-UP)
- PM3508 (S/N: BLM1-UP)
Introduction
Technical Information Bulletin replaces the 3May 2006 TIB "Genset VR6 Voltage Regulator Part Number 202-8634". Disregard the 3May 2006 TIB. Refer to the following information.
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.
Problem
Under certain load and load switching conditions, VR6 and K65-12B voltage regulators, part numbers 202-8634 Voltage Regulator As , 219-4078 Voltage Regulator As , 219-4079 Voltage Regulator As , 219-4080 Voltage Regulator As , and 219-4081 Voltage Regulator As installed with Permanent Magnet (PM) generators, may increase the generator output voltage. The output voltage may increase to the point where the generator set shuts down on "over voltage". Under such conditions, damage to the excitation system and connected load is possible.
Solution
Note for Self Excited Generators: VR6 or K65-12B voltage regulators used with Self-Excited (SE) generators do NOT require the external jumper wire between VR6 or K65-12B Terminal 28 and VR6 or K65-12B Terminal Ground (CH GND). Installing the external jumper wire or failing to remove the external jumper wire on a VR6 or K65-12B voltage regulator used with a SE generator will result in a short circuit that will damage the VR6 or K65-12B voltage regulator.
Prior to Replacing A Voltage Regulator:
Over correcting for lagging power factor, defective wiring and wiring terminations and/or a defective remote voltage adjust potentiometer will result in unstable voltage regulation. Adding excessive capacitive reactance to the connected load and/or an intermittent open in the voltage sensing circuit and/or in the remote voltage adjust circuit will cause the VR6 or K65-12B voltage regulator to over excite the generator, thus causing the generator output voltage to increase above the desired, set level. Ensure the addition of power factor correction capacitors does not ever increase the generator connected load power factor above unity (1.0), thus creating a leading power factor. If this condition is discovered, take necessary actions to assure the power factor correction scheme is properly designed and properly operating.
To demonstrate proper VR6 or K65-12B voltage regulator performance, operate the generator at no load and at the desired output voltage. Adjust the VR6 or K65-12B voltage regulator above and below the desired output voltage set point, then return to the desired output voltage set point. Apply connected load without power factor correction to again demonstrate proper VR6 or K65-12B voltage regulator operation.
Inspect all connecting wiring and wiring terminations to ensure no wire or wire insulation is damaged, that all wire terminals have been properly crimped or soldered, that all wire terminations are free of corrosion, and that all wire terminations are tight.
Next, measure any remote voltage adjust circuit resistance. Disconnect, float, and isolate connecting wires from VR6 or K65-12B voltage regulator terminals 6A and 7. At the wire ends, measure the remote voltage adjust circuit resistance. The circuit resistance should measure between zero Ohms and 10K Ohms +/- 5%. If the measurement reads either infinity or zero, again inspect the wiring and wiring terminations, including the solder joints at the remote voltage adjust potentiometer terminals. Look for damaged wire insulation or wires that may have become pinched between sheet metal, thus creating an open or short circuit, and for cold or cracked solder joints at the potentiometer terminals. Replace the wiring and reheat any solder joints as necessary. Use care to avoid excessive heat exposure to the potentiometer terminals when re-soldering the connecting wires to it.
Repeat the measurement.
If no wiring or solder joint defects are found and the circuit resistance still measures either infinity or zero, inspect and measure the remote voltage adjust potentiometer to ensure it is properly rated and properly operating. The potentiometer shall be rated for 10K Ohms +/- 5% and at least 2 Watts. It shall be equivalent to 127-9070 Potentiometer . At the potentiometer terminals to which the connecting wires are soldered and when the potentiometer is adjusted over its entire range the potentiometer should measure between zero Ohms and 10K Ohms +/- 5%. Replace the potentiometer as necessary. Use care to avoid excessive heat exposure to the potentiometer terminals when re-soldering the connecting wires to it.
Repeat the remote voltage adjust circuit resistance measurement from the connecting wire ends near the VR6 or K65-12B voltage regulator. If the circuit resistance is between zero Ohms and 10K Ohms +/- 5%, reconnect the connecting wires to VR6 or K65-12B terminals 6A and 7. Otherwise, make the above described repairs as necessary.
Permanent Magnet Generators:
When VR6 and K65-12B voltage regulators are used with Permanent Magnet (PM) generators and the generator neutral is bonded to the generator frame, ensure that there is an external jumper wire installed between VR6 or K65-12B Terminal 28 and VR6 or K65-12B Terminal Ground (CH GND). Another acceptable alternative is to install an external jumper wire between VR6 or K65-12B Terminal 28 and the generator neutral bar.
When VR6 and K65-12B voltage regulators are used with Permanent Magnet (PM) generators and the generator neutral is not bonded to the generator frame, for example in Marine Auxiliary installations where the generator neutral is floating, ensure that there is an external jumper wire installed between VR6 or K65-12B Terminal 28 and the generator neutral bar. Do not install the jumper from Terminal 28 to Ground (CH GND).
In each of the above described installations, the external jumper wire shall be constructed of 600V insulated, CSA and UL labeled, 18 AWG wire with properly sized locking fork terminals installed on each end.
Finally, check the VR6 or K65-12B voltage regulator for proper operation. Readjust the VR6 or K65-12B voltage regulator and remote voltage adjust potentiometer for the desired generator output voltage.