1. InformationReport title Siemens 2.3MW Drivetrain InspectionProject Siemens 2.3MW Drivetrain InspectionCustomer Inspection date 26 Jun 2016Site name Commissioning dateTurbine ID T29 Nacelle serial number XXXXTurbine type Siemens 2.3MW Inspector name XXXXTurbine manufacturer Siemens Approved by XXXX

2. Summary2.1. CommentsRomax monitoring detected a developing fault on the IMS B/C bearing inner race with an increasingtrend. The borescope inspection focused on this component.There is an axial crack on the inner race of the IMS C (generator side) bearing. Only a single crack wasobserved, though there could be others. This crack extended only part way across the surface of theraceway width.No evidence of debris in the parallel stage gearing indicates that secondary damage to othercomponents is not occurring yet.Note: T07 recently had a similar vibration detection by Romax monitoring. A borescope inspection inJune found an axial crack(s) on the same IMS generator side bearing inner race.

2.2. ConclusionsIt is recommended to schedule an uptower IMS replacement as soon as possible, ideally at the sametime as the IMS replacement on T07. When parallel stage bearings with axial cracks are in the earlystages of failure it may be possible to reuse the IMS assembly (HS Gear, LS Pinion, Shaft) and onlyreplace the TRB bearing pair. Consult with uptower service providers if this is an option with theWinergy 4456.5 gearbox and possible cost advantages compared to an entire IMS shaft replacement.As axial cracked bearings continue to operate the failure progresses to macropitting, which introducesdebris to other components in the gearbox. The shaft can also be damaged at the bearing seats (orhousing bores) necessitating an entire IMS assembly replacement and/or repairs to the housing.T29 can continue to operate without restrictions. Inspect in 6 months, including the filter magnet.Romax will monitor damage progression with vibration and temperature on the IMS downwindbearing.

Siemens 2.3MW Drivetrain InspectionT29 Siemens 2.3MW

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3. Severity rating system?.Unchecked Component to be inspected

NA.No access Component could not be viewed during inspectionMonitor vibration

Lim.Limited acceses Component could only be partially viewed during inspection due to limited accessMonitor vibration

1.Acceptable Component is in acceptable condition for its age.Inspect annually

2.Wear&tearComponent exhibits damage which may or may not affect the service life of the component. Component exhibits cosmeticissue. Continue to monitor, if damage progression is observed, plan replacement or repair action. Repair cosmetic issue.

3.Shortened service life Component exhibits damage which will reduce the service life.Increase inspection frequency and plan replacement or repair action.

4.Failed Component has failed or exhibits safety issue.Immediate repair or replacement.

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4. Major non-conformity issuesAssembly Component Failure mode RecommendationGearbox Bearing IMS-C axial crack Replace bearingGearbox Bearing IMS-C micropitting

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5. Inspection Details5.1. Gearbox

5.1.1. Gearbox serial numberComment: Recommendations:

1.Acceptable

5.1.2. Oil levelComment: Recommendations:

1.Acceptable

Failure mode: Low oil levelComment: oil level below markingsRecommendations: Correct Oil Level

5.1.3. Gearbox housingComment: Recommendations:

1.Acceptable

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Failure mode: Gearbox in situComment: Recommendations:

5.1.4. Gearbox HSPComment: Recommendations:

1.Acceptable

Failure mode: No damage notedComment: Recommendations:

5.1.5. Gearbox HSGComment: No damage found.Recommendations:

1.Acceptable

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Failure mode: No damage notedComment: Recommendations:

Failure mode: No damage notedComment: Recommendations:

Failure mode: No damage notedComment: Recommendations:

5.1.6. Gearbox LSGComment: Recommendations:

1.Acceptable

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Failure mode: No damage notedComment: Recommendations:

Failure mode: No damage notedComment: Recommendations:

5.1.7. Gearbox LSPComment: Recommendations:

1.Acceptable

Failure mode: No damage notedComment: Recommendations:

5.1.8. Bearing IMS-AComment: Recommendations:

Lim.Limited acceses

5.1.9. Bearing IMS-BComment: Recommendations:

1.Acceptable

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Failure mode: No damage notedComment: IMS-B bearing is a TRB pair with the IMS-C bearing found damaged (axial crack) needing replacement.Recommendations:

Failure mode: No damage notedComment: IMS-B bearing is a TRB pair with the IMS-C bearing found damaged (axial crack) needing replacement.Recommendations:

Failure mode: Comment: no access to IMS B/C bearing from within the gearbox, therefore access was gained from exterior cover.Recommendations:

5.1.10. Bearing IMS-CComment: The downwind IMS generator side bearing has an axial crack on the inner raceRecommendations: Bearing replacement needed

4.Failed

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Failure mode: axial crackComment: only 1 crack was observedRecommendations: Replace bearing

Failure mode: axial crackComment: crack extends part way across bearing inner raceway widthRecommendations: Replace bearing

Failure mode: axial crackComment: crack reaches the upwind edge of raceway widthRecommendations: Replace bearing

Failure mode: axial crackComment: view with different lightingRecommendations: Replace bearing

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Failure mode: axial crackComment: Recommendations: Replace bearingFailure mode: micropittingComment: early stages of fatigue damage (micropitting) along crack edgesRecommendations:

Failure mode: axial crackComment: location marking for future inspection, if neededRecommendations: Replace bearing

Failure mode: No damage notedComment: elsewhere the bearing looked good, with little to no evidence of the crack producing metal debris contaminationRecommendations:

5.1.11. Bearing HSS-AComment: Recommendations:

NA.No access

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5.2. Main Bearing

Failure mode: No damage notedComment: Recommendations:

5.1.12. Bearing HSS-BComment: Recommendations:

Lim.Limited acceses

Failure mode: Limited accessComment: Recommendations:

5.2.1. HousingComment: Recommendations:

1.Acceptable

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Failure mode: Main bearing in situComment: Recommendations:

5.2.2. Grease OverflowComment: Recommendations:

1.Acceptable

Failure mode: Grease overflow bucket Comment: acceptable amount and color of grease in main bearing panRecommendations:

5.2.3. Grease SampleComment: main bearing grease sample not takenRecommendations:

NA.No access

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- End of Report -

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