Technical Report

NREL/TP-500-49133

September 2010

Gearbox Reliability Collaborative: 

Gearbox Inspection Metadata

Kristin Munch and Mark McDade
National Renewable Energy Laboratory

1617 Cole Boulevard, Golden, Colorado 80401-3393

303-275-3000 • www.nrel.gov

NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency and Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

Contract No. DE-AC36-08-GO28308

Technical Report

NREL/TP-500-49133

September 2010

Gearbox Reliability Collaborative:

Gearbox Inspection Metadata

Kristin Munch and Mark McDade

Prepared under Task No(s). WE10.1132
NOTICE

This report was prepared as an account of work sponsored by an agency of the United States government. 

Neither the United States government nor any agency thereof, nor any of their employees, makes any 

warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or 

usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not 

infringe privately owned rights. Reference herein to any specific commercial product, process, or service by 

trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, 

recommendation, or favoring by the United States government or any agency thereof. The views and 

opinions of authors expressed herein do not necessarily state or reflect those of the United States 

government or any agency thereof.

Available electronically at http://www.osti.gov/bridge

Available for a processing fee to U.S. Department of Energy

and its contractors, in paper, from:

U.S. Department of Energy

Office of Scientific and Technical Information

P.O. Box 62

Oak Ridge, TN 37831-0062

phone: 865.576.8401

fax: 865.576.5728

email: mailto:reports@adonis.osti.gov

Available for sale to the public, in paper, from:

U.S. Department of Commerce

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

phone: 800.553.6847

fax: 703.605.6900

email: orders@ntis.fedworld.gov

online ordering: http://www.ntis.gov/ordering.htm

Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste
1

NREL/NWTC Gearbox Reliability Collaborative Database GearFacts Software

The Gearbox Reliability Collaborative (GRC) is a U.S. Department of Energy (DOE)/National 

Renewable Energy Laboratory (NREL) project to identify and understand premature failure of 

components in wind turbine gearboxes. These failures are a leading source of unplanned 

expense in the operation of commercial wind turbines. Analysis and root cause correction of 

these failures is critical to enhancing the commercial viability of wind power as a sustainable 

energy source. A key component of the overall GRC effort is the creation of a database of 

gearbox failure history. To this end, NREL has developed a software application called 

GearFacts that will be distributed to Database Collaborative participants to capture failure 

information when gearboxes are rebuilt. This publication names and describes each field used 

in GearFacts and can be used as a reference to the software’s design.

GearFacts software will be used at the time of a rebuild to guide rebuilders in defining and 

entering gear and bearing failure details including a photographic record of failure 

mechanisms. The owner of the gearbox will be able to use any information they have entered 

to maintain their own rebuild records and to produce reports on their fleet of gearboxes. The 

research community will be able to use aggregated data from the database to develop statistics 

on gearbox failure mechanisms, failure timing and, in some cases, costs. The aggregated 

reporting system will be secured and 'sanitized' to remove identifying data which might convey 

ownership (or other proprietary) information. In addition, participants in the collaborative will 

be able to access and utilize data from the testing and analysis portions of the GRC. 

For more information about the GRC and its background and proposed research agenda, please 

see “Improving Wind Turbine Gearbox Reliability” (NREL conference paper CP-500-41548), 

May 2007. You can access this paper at: http://www.nrel.gov/docs/fy07osti/41548.pdf.
2

MetaData Collection Elements

The list below describes the metadata elements associated with a gearbox inspection in the 

Gearbox Reliability Collaborative. 

Field name Field description

Rebuilder name Group or individual rebuilding gearbox.

rebuild site Where rebuilt.

gearbox owner

gearbox responsible contact Owner contact.

Gearbox responsible contact 

phone

Wind site name

Wind site address 1

Wind site address 2

wind site city

wind site state

Wind site zip

Wind site country

Site turbulence intensity Using standard nomenclature as available.

Site capacity factor Actual generation over potential generation.

Operating power Turbine rated output.

Gearbox install date The date the gearbox was installed on this turbine.

Gearbox startup date The date this gearbox first went into operation.

Gearbox shutdown date The date this gearbox was shutdown due to fault.

Gearbox removal date The date this gearbox was removed from the turbine.

Cumulative run time hours

The total amount of time this gearbox has run since last 

rebuild.

Turbine OK hours SCADA data which may be unavailable during rebuild.

Production since new or rebuilt

Total production in kWh since new (or last rebuilt if not 

new).

Line loss stops SCADA data which may be unavailable during rebuild.

Emergency stops SCADA data which may be unavailable during rebuild.

Wind site comments

Oil cooler installed Is an oil cooler installed?

Max online filter size in microns

Max offline filter size in microns

Sample collection point Where on gearbox was oil taken?

Sample collection date The date the sample was collected, after the failure?

Has dessicant breather Is a dessicant breather installed?

Lubricant comments

Failure date Date of the failure

How discovered Short description of how the failure was discovered.
3

Unusual conditions

SCADA data available Is SCADA data available for this gearbox?

SCADA data output format If SCADA data is available, what is its format?

Similar failed

The number of similar gearboxes that have failed on this 

site?

Similar running

The number of similar gearboxes that are running on this 

site?

Site terrain description A short description of the terrain of this site.

Terrain surrounding turbine A short description of the terrain around the turbine 

where this gearbox was installed.

Site climate Desert, ocean, or inland.

Inspection comments

Gearbox name

Manufacturer

Model

New or rebuilt? When last installed.

Rebuild location If rebuilt, above - shop, tower, unknown?

Power rating

Gear ratio

Serial number

{Image of the gearbox ID tag}

Storage

Please indicate whether the gearbox was stored indoors 

or outdoors after removal from turbine.

Mount Number of mount points.

Inspection date

Lead investigator

Assisting investigator

Attached images Images may be attached to any of the above areas and 

are critical to the usefulness of an incident report.

Enter data for lubricant:

Manufacturer Manufacturer of the lubricant used in this gearbox.

Type Grade Type and grade of lubricant used in this gearbox.

Last change date The date the lubricant was last changed

Lab analysis available Is a lab analysis report available for this lubricant?

Analysis frequency How frequently was the lubricant analyzed?

Lab used The name of the lab that analyzed the lubricant.

Oil temperature control low setpoint

Fahrenheit/centigrade

Oil temperature control high setpoint

Fahrenheit/centigrade

Enter for each gear:

Gear type Helical/spur.

Teeth The number of teeth on this gear.

Gear handedness Left/right
4

Outside diameter The outer diameter of the gear.

Face width The face width of the teeth.

Whole depth of teeth

Tooth thickness span

Tooth thickness top land

Gear comments Comments concerning the inspection of this gear

Failure classification

Choose a classification category, and a subclassification.

Enter for each bearing:

Bearing type

Bearing orientation

Bearing set orientation

Make Maker of this bearing.

Country Country of make of this bearing.

Inner race outside diameter

Inner race inside diameter

Outer race outside diameter

Outer race inside diameter

Width

Number of rollers

Roller profile

Roller diameter

Roller length

Cage type

Cage material

Comments Comments concerning the inspection of this bearing

Failure classification

Choose a classification category, and a subclassification
F1147-E(10/2008)

REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing the burden, to Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents 

should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a 

currently valid OMB control number.

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

September 2010

2. REPORT TYPE

Technical Report

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Gearbox Reliability Collaborative: Gearbox Inspection Metadata

5a. CONTRACT NUMBER

DE-AC36-08-GO28308

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

K. Munch and M. McDade

5d. PROJECT NUMBER

NREL/TP-500-49133

5e. TASK NUMBER

WE10.1132

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory

1617 Cole Blvd.

Golden, CO 80401-3393

8. PERFORMING ORGANIZATION

REPORT NUMBER

NREL/TP-500-49133

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)

NREL

11. SPONSORING/MONITORING

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service

U.S. Department of Commerce

5285 Port Royal Road

Springfield, VA 22161

13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

NREL has developed a software application called GearFacts that will be distributed to Database Collaborative 

participants to capture failure information when gearboxes are rebuilt. This publication names and describes each 

field used in GearFacts and can be used as a reference to the software’s design.

15. SUBJECT TERMS

wind; gearboxes; GRC; database; failure analysis; failure history.

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 

OF ABSTRACT

UL

18. NUMBER 

OF PAGES

19a. NAME OF RESPONSIBLE PERSON

a. REPORT

Unclassified

b. ABSTRACT

Unclassified

c. THIS PAGE

Unclassified 19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98)

Prescribed by ANSI Std. Z39.18