Spring Isolator Installation and Adjustment Procedure for Certain Generator Sets with 3500 Gas Engines{1021, 7002} Caterpillar

Engine:

G3512 (S/N: CRN1-UP; CSP1-UP)

G3512E (S/N: SSR1-UP; NGS1-UP)

G3516 (S/N: L6A1-UP; L6E1-UP; L6F1-UP; L6G1-UP)

G3516B (S/N: L6H1-UP; L6J1-UP)

G3516C (S/N: F6D1-UP; F6E1-UP; F6F1-UP)

G3516E (S/N: F6G1-UP)

G3516H (S/N: GLM1-UP; GLN1-UP)

G3520C (S/N: GZA1-UP; GZB1-UP; GZJ1-UP; GZL1-UP; GZN1-UP; RLP1-UP; LGS1-UP)

G3520E (S/N: GZE1-UP)

Introduction

Do not perform any procedure in this special instruction until the information has been read and understood. Spring isolators are used in order to reduce vibration and noise. This special instruction provides the necessary information that is required for installing and adjusting spring isolators on the gas 3500 series engine products.

Safety Section

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At operating temperature, the engine coolant is hot and under pressure. Steam can cause personal injury. Check the coolant level only after the engine has been stopped and the filler cap is cool enough to touch with the bare hand. Remove the filler cap slowly to relieve pressure. Cooling system conditioner contains alkali. Avoid contact with skin and eyes to prevent personal injury.

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Personal injury or death can result from high voltage. When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present. Improper test equipment can fail and present a high voltage shock hazard to its user. Make sure the testing equipment is designed for and correctly operated for high voltage and current tests being made. When servicing or repairing electric power generation equipment: Make sure the unit is off-line (disconnected from any utility and/or other generators that can provide power service), and either lock out or tag as "DO NOT OPERATE". Remove all fuses. Make sure the generator engine is stopped. Make sure all batteries are disconnected. Make sure all capacitors are discharged. Failure to do so could result in personal injury or death. Make sure residual voltage in the rotor, stator and the generator is discharged.

Adjust Spring Type Isolators

The part numbers associated with this Special Instruction are listed in Table 1.

All of the generator sets are to be installed on anti-vibration isolators. The isolators must be adjusted after the generator set is installed properly at the on-site location with all of the auxiliary equipment connected. The isolators must be adjusted correctly in order to ensure that the isolators are level and the generator is properly aligned to the engine. If the generator set is hard mounted to a foundation, the generator must be leveled properly.

The weight on each isolator should be approximately the same. Proper weight distribution is achieved by making sure that all of the springs are compressed equally. Ensure that none of the springs are collapsed. The isolator will not be able to isolate the transmitted vibrations if the springs are fully compressed.

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Illustration 1	g03722645
Two typical examples of spring type Isolators (1) Bolt for adjusting the isolator (2) Locknut (3) Rail bottom surface interface to isolator (4) Isolator springs (5) Foundation (A) Distance to be adjusted 6.35 mm (0.25 inch) to 12.7mm (0.5 inch)

Note: If any of the springs are fully compressed and cannot be adjusted, verify that the isolator has been correctly sized for the application. There are springs that are available with a different spring rate.

1. The isolator springs (4) must be adjusted to ensure that the weight of the generator set is equally distributed on all of the isolators. This adjustment also ensures that the generator set is level. Refer to Illustration 1.

Note: Do not measure the height of the isolator from the floor. The floor may not be even. Measure distance (A) between the upper housing and the lower housing to ensure that all isolators carry the weight of the generator set evenly.

2. The spring for each isolator will be compressed by the weight of the generator set. Use a ruler in order to measure the distance (A) between the upper housing and the lower housing for each isolator. Adjust mounting so that upper housing clears the lower housing by distance (A) .

3. Use the adjusting bolt (1) for the isolator in order to adjust the amount of weight that is placed on each isolator. The weight distribution of the generator set should be approximately the same amount for each isolator.

   Loosen the locknut (2) in order to be able to turn the adjusting bolt (1) for the isolator. If the weight distribution is not equal, then the springs for one isolator will be compressed more than the springs of another isolator. Turn the adjusting bolt (1) counterclockwise in order to back the adjusting bolt off for the isolators that have the springs compressed more. Turn the adjusting bolt clockwise on the isolators that have the springs compressed less. The total rise of the rail (3) above the foundation (5) will not change but the weight will become distributed more evenly between the isolators.

   Note: Some generator sets may be shipped with larger isolators installed under the generator. The larger isolators are used if the generator is over-sized. An over-sized generator may cause the center of gravity of the generator set package to shift rearward. If a generator set has been shipped with large isolators installed under the generator, adjust the generator isolators as one set. Then, adjust the isolators under the engine as another set.

4. If the generator set is equipped with a radiator, verify that all of the springs for the radiator isolators are equally compressed. Adjust the springs for the radiator isolators if the springs are not equally compressed. The isolators that are used under the radiator may have a spring rate that is different. The isolators used under the radiator carry only the weight of the radiator. The spring compression of the isolators used for the radiators may not need to be identical to the spring compression for main base rail isolators.

5. After all of isolators are adjusted, secure the position of each adjusting bolt. Tightening locknut (2) against the inside surface of the rail (3) on the generator set.