Reduced Service Life of the Flexible Coupling on 1500 RPM G3520C and on 1500 RPM G3520E Generator Set Engines{3252} Caterpillar

Generator Set:

G3520C (S/N: MAD1-UP; GZK1-UP; GZN1-UP; CWW1-UP; GHE1-UP; JBX1-UP)

G3520E (S/N: GZH1-UP; HAL1-UP; GHR1-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.

Problem

Failures of the 247-0308 Flexible Coupling Gp have been reported on some G3520C and on G3520E Generator Set Engines. Due to the lower stiffness of this coupling, the resonance of the engine drive train is close to the operating speed of the generator set. This causes the damper to absorb more of the torsional energy. This raises the temperature of the fluid in the damper. The effectiveness of the damper is reduced by increased fluid temperature. Once the damper becomes less effective, flexible coupling failures can occur due to the extra torsional load and the heat that is generated.

High wear rates have been seen on the 5N-3765 Flexible Coupling Gp that is used on some G3520C and on G3520E Generator Set Engines. The root cause is still under investigation.

Solution

Illustration 1	g01232173

Illustration 2	g01232217
(1) Damper (2) 8T-2821 Temperature Indicator

Install temperature indicator (2) onto the perimeter of the damper. Refer to Illustration 2.

Monitor the temperature of the damper daily by using an infrared temperature gun. Measure the temperature at the perimeter of the damper. Shut down the engine if the reading on the infrared temperature gun indicates that the temperature is above 90 °C (194 °F). Check the temperature indicator (2). If the temperature indicator also indicates damper temp above 90 °C (194 °F), then the 247-0308 Flexible Coupling Gp must be replaced with the 5N-3765 Flexible Coupling Gp .

Reducing the engine load can reduce damper temperature. Reducing the engine load can be a temporary solution in order to extend the life of the damper and of the flexible coupling. The temperature of the damper can be reduced below 90 °C (194 °F) by lowering the engine load by approximately ten percent.

Replace the damper if the temperature of the damper is measured above 100 °C (212 °F) at any point.

Please report any failures of the 247-0308 Flexible Coupling Gp to your engine technical communicator for contact with the Caterpillar Dealer Solution Network (DSN). Use the DSN for questions or for assistance on this matter.

In the event of a failure by the coupling, an entry must be made to the DSN as soon as possible. The following information is required for the DSN:

• The serial number of the engine or of the package

• Engine hours

• Failure mode

• Hours on the failed components

• Profile for the load at the site

• Logged events from the Electronic Control Module (ECM)

• Any applicable engine data that has been logged by the switchgear

Illustration 3	g01232244
(1) 5N-3272 Rubber Coupling Boot (2) Wear step (A) Thickness of a new boot (B) Replacement thickness

Inspect boot (1) at a minimum of 1500 hour service intervals. Look for wear steps (2) in boot (1). A measurement of the wear step can also be taken at the same time. Use the results of the inspection to adjust the service interval.

Do not measure the wear step directly due to displaced rubber material. Measure the thickness at the highest point of wear. Refer to Table 1. Replace boot (1) when the boot is worn to thickness (B).