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Proper Grounding for the 161-0797 Governor Control As {1264, 1408} Caterpillar

3412 (S/N: 2WJ1-UP; 81Z1-UP; 25Z1-UP)
3412C (S/N: BAK1-UP)
3508 (S/N: 5XM1-UP; 3LS1-UP; 23Z1-UP; 70Z1-UP)
3508B (S/N: S2A1-UP; S2B1-UP; 3DM1-UP; 4GM1-UP; 6PN1-UP; 1TW1UP; 2HW1-UP; 3DW1-UP)
3512 (S/N: 6PM1-UP; 3MS1-UP; 3WS1-UP; 24Z1-UP; 67Z1-UP)
3512B (S/N: NSC1-UP; AAG1-UP; S2G1-UP; S2H1-UP; 8EM1-UP; 8RM1UP; 6WN1-UP; 1PW1-UP; 2GW1-UP; 4AW1-UP; 5AW1-UP)
3516 (S/N: 4XF1-UP; 5SJ1-UP; 7KM1-UP; 3NS1-UP; 3XS1-UP; 73Z1-UP)
3516B (S/N: CBN1-UP; 6HN1-UP; 7RN1-UP; 9AN1-UP; S2P1-UP; S2R1UP; 1NW1-UP; 2FW1-UP; 2JW1-UP; 3CW1-UP)
G3406 (S/N: 1RK1-UP)
G3606 (S/N: 3XF1-UP)
G3608 (S/N: 4WF1-UP)
G3612 (S/N: BKE1-UP; 1YG1-UP)
G3616 (S/N: BLB1-UP; 4CG1-UP)
Generator Set:
C9 (S/N: SJB1-UP)
C-12 (S/N: BCY1-UP)
C18 (S/N: MGS1-UP; CYN1-UP; STD1-UP)
3126B (S/N: BDZ1-UP)
3406E (S/N: 8AZ1-UP)
3412C (S/N: 4BZ1-UP; 9EP1-UP; RTY1-UP)
G3412 (S/N: KAP1-UP; R7A1-UP)
3456 (S/N: C1G1-UP; CAH1-UP; CBX1-UP; CCB1-UP; C3G1-UP; C4G1UP)
3508 (S/N: CNF1-UP; CAW1-UP)
3508B (S/N: 5KW1-UP; CNB1-UP; BGX1-UP; BGZ1-UP; PTN1-UP;
3512 (S/N: CMJ1-UP; FDR1-UP)
3516 (S/N: CMD1-UP; CAL1-UP)
Power Module:
PM3412C (S/N: 5FL1-UP; CAJ1-UP)
PM3508B (S/N: BLM1-UP)
PM3512 (S/N: BRF1-UP)
PM3512B (S/N: BNR1-UP)
PM3516 (S/N: CAC1-UP)
PM3516B (S/N: BPD1-UP; PPS1-UP)
Do not perform any procedure that is outlined in this Special Instruction until the
entire instruction has been read and understood.
This Special Instruction describes the proper grounding procedure for the 161-0797
Governor Control As .
Grounding Practices
Failure to connect the unit to a suitable grounding electrode can result
in electrical shock and may cause injury or death.
Proper grounding is necessary for optimum engine performance and reliability.
Improper grounding will result in electrical current paths that are uncontrolled and
Uncontrolled electrical circuit paths can result in damage to main bearings, to
crankshaft bearing journal surfaces, and to aluminum components. Uncontrolled
electrical circuit paths can also cause electrical activity that may degrade the engine
electronics and communications.
Ensure that all grounds are secure and free of corrosion.
Grounding Procedure
Illustration 1 g00015449
Ground symbol
The ground screw for the chassis is identified with the ground symbol. Refer to
Illustration 1. This point must always be connected to the system ground at a central
point. The housing for the Load Sharing Module (LSM) is painted. This painted
housing will not provide a good ground connection. Use the designated ground screw
for this purpose.
Resistance from the ground screw of the module's chassis to the engine ground must
be minimal. A resistance that is not greater than 0.1 ohms is optimal. Test the
resistance in order to ensure compliance. The engine ground refers to the engine
ground that is associated with this LSM. A greater resistance increases the risk of a
potential hazard and of equipment damage.
Avoid ground loops. Do not paint ground points.
The following publications may provide additional information:
IEEE Standard 142" Recommended Practice for Grounding of Industrial and
Commercial Power Systems"
IEEE Standard 1100" Recommended Practice for Powering and Grounding
Sensitive Electronic Equipment"
Electrical codes and service publications may provide additional requirements.
Shielded Wiring
The following considerations are the primary purposes for grounding equipment:
Safety of personnel
Improved equipment operation
Continuity of service
There are four main reasons for having grounded systems:
Protection against a lightning strike
Reduction in the emission of noise
Integrity of the signal
Terminate the following shields at one end only. Limit the length of the shields'
breakouts to less than 50.8 mm (2 inches).
The shield for the input signal from the synchronizer must be connected to
terminal 21 on the module. Leave the shield floating at the synchronizer's end.
The shield for the speed trim potentiometer must be connected to terminal 21
on the module. Leave the shield floating at the potentiometer end.
The shield for the pulse width modulated output (PWM) must be connected to
terminal 21 on the module. Leave the shield floating at the engine control's
Always connect the shield for the load share module to terminal 12 on the module.
This terminal is not chassis ground. Never connect the shield for the load share
module to chassis ground. Refer to the wiring diagram in Illustration 2.
Illustration 2
Diagram for the shielded wiring for the control signals
The control wiring must be run separately from the AC power's wiring in order to
avoid coupling noise from the AC power's wiring.
Limit the length of most of the cables that are connected to the module to less than 30
m (98 ft). Keeping the cable length shorter than 30 m (98 ft) will minimize antenna
effect, noise, and high ground resistance.
The following components can have cables that are longer than 30 m (98 ft).
Potential transformers (PT)
Current transformers (CT)
Cables for the load share module
Cables for the PWM output
Sensitivity to Electrostatic Discharge (ESD)
Electronic controls contain parts that are sensitive to static electricity. In order to
prevent damage to these parts, observe the following precautions:
Discharge static electricity from the body before handling the control. The
power to the control must be in the Off position. Maintain contact with a
grounded surface when the control is handled.
Avoid all plastic, vinyl, and styrofoam material that is used around electronic
Do not touch the components or the conductors on a printed circuit board with
your hands or with conductive devices.
Do not touch connector terminals with your hands or with conductive devices
without first discharging the static electricity from your body. Wear a strap for
electrostatic discharge while you work with electronic controls.