Moventas GE 1.5 Extra Life Gearbox Achieves 4x Life

© 2016 Sentient Science Corporation – Confidential & Proprietary
Agenda:
1. Introductions
2. Sentient Science Overview and Our Gearbox Partnerships
3. Moventas Extra Life Gearbox Overview – Why Develop and Core Upgrades
4. Technical Assessment of Moventas Upgrades and Life Extension Outcomes
5. Next Steps
Moventas GE 1.5 Extra Life Gearbox Achieves 4x Life

SentientScienceCorp.-Proprietary/PrivateLevel1
Presenters:
Natalie Hils – Sentient
Manager of Revenue Marketing
nhils@sentientscience.com
+1 716.807.8655
Dr. Raja V. Pulikollu – Sentient
Vice President of Implementations,
Chief Materials Scientist
rpulikollu@sentientscience.com
+1 937.241.1144
Kari Huttunen - Moventas
Director, Business Development North America
Kari.Huttunen@moventas.com
+1 503.477.3750

Sentient Science Overview – Core Goals, IP, and Industries
A Trusted Third Party Enabling Life Extension of Rotating Equipment in two ways:
1. Computational Testing & Demand Management for Suppliers 2. Asset Management for Operators
☑ Life Extension☑ Root Causes☑ Predict Earlier
Key Industries Served
WIND ENERGY
• 200,000 Global units
• 20,000 assets under contract
AEROSPACE
• Rotorcraft, Fixed Wing, & Defense
• (15 Years of R&D)
RAIL
• Wheel Rail Interface
• Top of the Rail Friction Modifier and
Lubricants

Sentient Science Current Approach to Gearbox/Bearing Modeling
• Physical tests are unavoidable, but also
expensive
• Sentient offers it’s DigitalClone technology to
provide a sophisticated virtual test Lab
• Virtual test labs can support physical tests
• Reduce costs
• Go into physical testing with more confidence
• DigitalClone can determine bearing and gear
life based on:
• Bearing material (Hardness, inclusions, etc)
• Surface finish (grinded, polished, superfinished,
etc.)
• Lubrication properties (pressure and heat
dependent viscosity, etc.)

Sentient Science Overview – DigitalClone® Live Software for Operators
User Interface Screenshots and Solutions for Operators – “Buy on Life”

GE 1.5MW wind turbines have experienced premature failures in the field before
expected L10 20 year life
Operators have experienced repeat failures of spare gearboxes that did not meet
reliability expectations, and this has led to rising Major Component Repair and
Replacement costs after end-of-warranty date.
Moventas saw an opportunity to improve the design and components of known failure
modes to reduce future failures, reduce O&M cost, and improve availability
Moventas requested Sentient Science to provide third-party assessment of these key
technology upgrades and quantify the life extension benefits for owner-operators
Why Moventas Developed GE 1.5MW Extra Life Gearbox?
Reduce Future Wind Turbine O&M costs and maintain high turbine availability

Moventas Extra Life Technology Upgrades:
1.1 Case carburized ring gear – Benchmark performance against industry
standard to show the difference in component durability.
1.2 Integrated planet gear bearings - Prove that the 2-row arrangement is
more robust than a 4-row arrangement, and benchmark the performance
against a industry standard.
1.3 Improved tooth surface roughness – Prove that the surface roughness
of Ra=0.3 will improve micropitting resistance compared with Ra=0.6.
1.4 Improved material specifications in geared components – Prove that
new material specification is better than old one and provide benchmark
analysis against industry standard
1.5 New material in bearings – Prove that White Etch resistant bearing is
more resistant to white etching cracks than old design and industry
standard.
IMS Pinion

DigitalClone Fatigue Life Simulations
Procedure, assumptions and technical details
Given:
• GE 1.5 MW Turbine
• Material samples provided by Moventas
• Technical details on Moventas PLH-1100, PLH-1100-XL
gearbox improvements
Assumptions:
• Material properties from Sentient’s Library as needed
Procedure:
• Loading analysis
• Mixed elastohydrodynamic lubrication analysis
• Lifing calculations
• Post processing and interpretation of results
• Sentient conducted in-detail material
characterization analysis on Moventas provided
bearing samples to obtain the following technical
details, input to DigitalClone material and life
prediction model
– Grain size and morphology
– Case microstructure, core microstructure,
case-core transition region microstructure
– Defects, non-metallic inclusions size
distribution, if any
– Material imperfections, retained austenite,
grind burn etc.
– Residual stress analysis
– Surface roughness analysis

Moventas GE 1.5 Extra Life Gearbox Upgrades - Summary
Integrated
Planet Gear
Bearing
Case
Carburized
Ring Gear
New Bearing
Materials for
High Speed Stage
Improved Tooth
Surface Roughness
In Gears
Improved
Gear Material
Specifications
=
BRG
1
BRG
2
Black oxide layer
+ White Etch Resistant
60.8 61.2 61.9 61.2 60.8
56.7
58.7
53.8
52 52.3
48.7
46.8 47
44.3
40.8 40.5
30
35
40
45
50
55
60
65
0 500 1000 1500 2000 2500 3000 3500
Rockwell:HRC
Depth: Microns
0.5Kg
GE 1.5 Extra Life Gearbox
Achieves 4x Life

Legacy Gearbox vs. Moventas PLH-1100 Critical Locations:
Legacy Gearbox Moventas PLH 1100.2
Critical
Components
Normal
Roller Load
(N)
Contact
Stress (GPa)
Normal
Roller Load
(N)
Contact
Stress (GPa)
LSS_UW 30,887 1.470 37,433 1.264
LSS_DW 34,488 1.385 11,829 0.929
IMS_UW 15,969 0.965 14,451 1.074
IMS_DW 65,508 1.218 71,752 1.300
HSS_UW 29,961 1.174 33,225 1.167
HSS_DW 13,451 1.129 10,922 0.922
PGC 51,208 1.880 148,442 1.741
Highest Stress
Lowest Stress
Input Power
Output Power
Planet Gear Bearing
and Planet Gear
Low Speed Bearing
Upwind
Intermediate Speed Shaft
Bearing Upwind
High Speed Shaft
Bearing Upwind
Planetary Carrier
Bearing Upwind
Planetary Carrier
Bearing Downwind
Low Speed Bearing
Downwind
Intermediate Speed Shaft
Bearing Downwind
High Speed Shaft
Bearing Downwind
Sun
Pinion
Low Speed
Shaft Gear
Intermediate
Speed Shaft
Pinion
High Speed
Shaft Pinion
Intermediate
Speed Shaft
Wheel
• Sentient modeled the differences in GE1.5 MW Moventas PLH 1100.2 and Legacy Gearbox
gearboxes
• Overall, PLH-1100.2 bearings have relatively lower stresses than Legacy Gearbox
• Moventas PLH-1100.2 integrated planet gear bearing design results in lower stresses

Advanced Technology #1: New Bearing Materials
for High Speed Shaft Bearings (HSS)
Black Oxide (BO)
White Layer Etch Resistant

MnS + Oxide
MnS + Oxide
Component Hardness, HRC
Inner race 60
Outer race 61
Roller 61
Outer Race
Case Core
Case Core
• Non-metallic MnS, Oxide and TiN inclusions are observed in the inner and outer raceway as-large-as (ALA) 35 and 50 µm, respectively
• Inner raceway consists of Bainitic microstructure whereas Outer race has good martensitic microstructure
• Roller is relatively clean and have good tempered martensitic microstructure
• Black oxide thickness varies from 0.8 µm to 1.5 µm
Inner Race
Black oxide layer
Advanced Technology #1: New Bearing Materials for HSS Bearing - BO

62 62 62 62 62 62
59
56
51
47 47 47 46 47 47
60
62 62 62 62
61 61 61 61 61
40
45
50
55
60
65
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Rockwell:HRC
Depth: Microns
White Etch Resistant Bearing
IR
OR
RLR
OxideCase Case
Inner
Race
• IR is case hardened, whereas both OR and
roller are through hardened.
• IR case hardness is 62 and core is 47 HRC.
• Average roughness of OR and roller is 62 and 61
HRC, respectively.
• Presence of globular oxides, MnS and TiN
inclusions ALA 10 µm were observed in Inner
Race
• High Cr % of 2.99% in the matrix
Advanced Technology #1: New Bearing Materials for HSS Bearing – White Etch Resistant Bearing

• Sentient conducted total 1,000 contact fatigue life simulations at 1.6 MW nominal torque and speed to predict the
dominant damage mode and life
- Pitting/spalling/wear
• PLH 1100.2 XL HSS bearings have relatively lower contact stresses
• White Etch Resistant and BO material quality is superior and have additional protection in the form of black oxide coating
• DigitalClone predicts both White Etch Resistant and BO bearings to meet L10 life of 20 years.
• However, BO predicted to have 3% probability of failure (POF) in less 20 years due to non-metallic inclusions. BO bearing
predicted to have relatively lower life under high torque/uprate conditions
• White Etch Resistant is superior in protection against white etch cracking resulting from heat treatment and improved
microstructure
• Sentient recommends to use White Etch Resistant bearing at HSS and HSIS bearing locations to avoid axial cracking
RVE Size: 2.45mm by 1.57 mm
No. of grains: 11,646
Bearing Contact surface
Advanced Technology #1: New Bearing Materials
White Etch Resistant and BO HSS Bearings Fatigue Life Simulation Results & Recommendations
Bearing Type L10-Fatigue Life , years Contact stress, GPa
HSS_White Etch Resistant 20 1.2 (UW-side)
HSS_BO 20 1.2 (UW-side)

Advanced Technology #2: Integrated Planet Gear
Bearings

Component Supplier A, HRC Supplier B, HRC
Races 61 60
Roller 61 60
MnS+Oxide
Case Core
Case Core
Supplier A
Supplier B
• Supplier A: Good hardness, Tempered martensitic microstructure with slight
carbide banding and non-metallic inclusions as large as 10 µm
• Supplier B: Good hardness, Bainitic microstructure, slight carbide banding, and
non-metallic inclusions as large as 30 µm
Advanced Technology #2: Integrated Planet Gear Bearings, 2-Row: Supplier A vs Supplier B
MnS+TiN+Oxide
Case Core

Advanced Technology #2: Legacy Planet Gear Bearings, 4-Row: Supplier A vs. Supplier B
Supplier B
Case Core
Inclusion
• Supplier A: Good hardness, tempered martensitic microstructure, carbide
banding and non-metallic inclusions as large as 50 µm
• Supplier B: Good hardness, Bainitic microstructure and non-metallic
inclusions as large as 50 µm
Case Core
Mulit-phase inclusion
Butterfly formation
Supplier A
Component Supplier A, HRC Supplier B, HRC
Races 63 61
Roller 62 61

Legacy GBX –
Supplier B
PLH-Supplier B
Legacy Gearbox –
Supplier A
PLH-Supplier A
• Sentient conducted 2000 fatigue life simulations to compare PLH1100 planet
bearing with Legacy gearbox
• DigitalClone fatigue life simulations predicted:
• Highest fatigue life of PLH 1100 -XL-A bearing due to clean material
quality and relatively lower contact stress
• Fatigue life of PLH 1100 XL- B is higher than Legacy Gearbox due to
lower contact stress and better material quality
• Legacy gearbox planet shaft bearing fatigue lives are lower as they
experience higher contact stresses and have lower material quality
• The material quality difference between Bearing A MVS and Legacy is
more significant than Bearing B, hence the huge difference in life
Advanced Technology #2: Integrated Planet Gear Bearings
PLH 1100 and Legacy Gearbox Bearing A&B Fatigue Life Simulation Results
Case Study
Max
Contact
Pressure
(MPa)
L10
rev
L50
rev
L90
rev
Life
Improvement
PLH 1100_XL – A 1741 2.67E+09 1.31E+11 1.57E+12 216x
PLH 1100_XL - B 1741 3.18E+08 5.60E+09 3.48E+10 26x
Legacy - A 1880 3.78E+07 8.36E+08 6.01E+09 4x
Legacy - B 1880 1.05E+07 1.35E+09 2.97E+10 1x

Advanced Technology #3: Case Carburized Ring Gear

Legacy Gearbox Ring Gear Material Quality
59
49
38
33 31 32 35 33 35 35 34 35 33 32 34
28 31 33 30 31
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Rockwell:HRC
Depth: Microns
Ring Gear
Max Hardness: 59 HRC
Min Hardness: 28 HRC
• Ring gear is case carburized
with max. surface hardness of
59 HRC and min. hardness of 28
HRC.
• Case depth is 100µm
• MnS, Tin and Oxide inclusions
as large as 40 µm
• Ring gear is case hardened and
contains intergranular Cracks,
Nitrided layer on surface, Fe3N
grain boundary networks in the
microstructure. These
abnormal microstructure
features lead to early crack
nucleation and premature
failures
Contact surface
Indents
MnS inclusion
Tri-phase inclusions

Legacy Gearbox
Ring gear
Max Contact
Pressure
Pmax
(MPa)
L10,
cyc
L50,
cyc
L90,
cyc
PLH-1100.2 1371
20 years life ( based on clean material quality and
no serial defects)
Legacy Gearbox 1371 1.60E+07 6.80E+08 7.42E+09
• Sentient conducted a total of 1000 contact and bending
simulations to predict the effect of case carburization on
fatigue life
• PLH 1100 XL ring gear have L10 fatigue life of 20 years
based on assumption of clean material quality and no
serial defects
• Legacy Gearbox ring gear with poor material quality
predicted to have life less than 7 years of L10 fatigue life
PLH 1100 XL and Legacy Gearbox– Ring Gear Fatigue Life Simulation Results &
Recommendations

Advanced Technology #4: Improved Material
Specifications in Geared Components

IMS pinion with inclusions
IMS pinion
Max Contact
Pressure
(MPa)
L10,
cyc
L50,
cyc
L90,
cyc
With no inclusions 1330 20 years life ( based on clean material quality)
With inclusions 1330 5.64E+06 9.75E+08 2.60E+10
• Sentient conducted contact fatigue life simulations to study
the impact of non-metallic inclusions on IMS pinion fatigue lfie
• PLH 1100.2 IMS pinion with no presence of detrimental
inclusions is predicted to meet design L10 life of 20 years
based on clean material quality and no serial defects
• PLH 1100.2 with detrimental inclusions (ALA 150 µ)
predicted to have L10 fatigue life of less than 5 years
• It is recommended to use IMS pinion with martensitic
microstructure with non-metallic MnS inclusions of size
ALA <30µm and lower inclusion density for superior
fatigue life
Advanced Technology #4: Improved Material Specifications PLH 1100 IMS Pinion – Effect of
Inclusions Fatigue Life Simulation Results & Recommendations

Advanced Technology #5: Improved Tooth Surface
Roughness

Ra = 0.3
Ra = 0.01
Ra = 0.6
Sun Pinion
with Ra, µm
Pmax
(MPa)
L10, cyc L50, cyc L90, cyc Life Factor
0.01 1781 9.08E+06 5.24E+07 6.67E+08 2.9x
0.3 1781 6.89E+06 3.75E+07 2.51E+08 2.2x
0.6 1781 3.10E+06 2.45E+07 1.77E+08 1x
PLH 1100 XL –Sun Pinion Fatigue Life Simulations and Recommendations
• Sentient conducted RCF simulations to predict the effect of
surface finish on Sun Pinion fatigue life
• Compared to Ra of 0.6 µm, Sun Pinion with 0.3 µm has a
significant increase in L10 fatigue life (by a factor of 2.2x)
• Increase in RCF L10 life (factor of 2.9x) with superfinish
(Ra: 0.01 µm)
• It is recommended to have Ra of 0.3 µm as a minimum surface
finish specification
Mixed-EHL pressure profiles for progressively smoother surface roughness
Ra: 0.01µmRa: 0.2µmRa: 0.3µmRa: 0.6µm
Advanced Technology #5: Improved Tooth Surface Roughness

Summary of Findings
• Sentient completed modeling and comparison of PLH 1100, XL and Legacy Gearbox performance considering
design, manufacturing, materials, and loading conditions.
• Overall, PLH-1100 bearings have relatively lower stresses than Legacy Gearbox
• PLH-1100 integrated planet gear bearing design results in 8% lower contact stresses
• XL gearbox predicted to meet design L10 life of 20 years due to overall improvements in using advanced bearings, case
carburized ring gear, better surface finish and clean martensitic microstructure with no presence of detrimental inclusions
• Compared to Black Oxide (BO) bearing, White Etch Resistant bearing is superior in protection against white etch
cracking resulting from heat treatment and improved microstructure
• XL gearbox improvements can be reused in Moventas future gearbox designs, rebuilds and uptower repair services

DigitalClone Recommendations
1. Sentient recommends to use White etch resistant case carburized bearing with high Cr-content in XL gearbox HSS
and HSIS bearing locations
2. Black oxide and case carburized integrated planet gear bearings with retained austenite of 20-25% is
recommended
3. For ring gear, case carburized martensitic microstructure with a case depth of about 1500 µm and case hardness
of >60 HRC is recommended
4. The following microstructural features need to be avoided or reduced for better fatigue performance
1. Needle-like non-metallic MnS and metallic TiN inclusions of size >30µm and higher inclusion density
2. Carbide banding
3. Oxide/intergranular oxidation sites
4. Grain coarsening and de-carburization layer
5. It is recommended to have Ra of 0.3 µm as a minimum surface finish specifications to reduce asperity interactions
and increase in XL gears and pinions RCF life

1. Lowest Lifetime Cost-of-Ownership
• Upgrades reduce future repeat failures and O&M costs after end-of-warranty
• Condition Monitoring 24/7 to follow up the health of your gearbox
• Excellent up-tower serviceability
2. Lowest Risk
• The strongest planetary stage featuring case carburized ring gear & planet wheels and
integrated planet gear bearings with more than 15 years proven track record .
• Industry-leading 5 year warranty to minimize risk due to Moventas end-to-end quality
control and manufacturing processes
3. Life Extension Revenue for GE 1.5MW
• Upgrades enable operators to implement life extension of wind farms to 25-30+ years,
so gearbox continues to operate and maximize availability
Benefits of Moventas GE 1.5MW Extra Life Gearbox
Moventas Benefits can be Confirmed on Your Sites with DigitalClone Live

Thank you!

Questions:
Natalie Hils – Sentient
Manager of Revenue Marketing
nhils@sentientscience.com
+1 716.807.8655
Dr. Raja V. Pulikollu – Sentient
Vice President of Implementations,
Chief Materials Scientist
rpulikollu@sentientscience.com
+1 937.241.1144
Kari Huttunen - Moventas
Director, Business Development North America
Kari.Huttunen@moventas.com
+1 503.477.3750

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