GEAR-RING 1695594 - Caterpillar

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)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)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)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