IEC 61400-4:2012

Wind turbines — Part 4: Design requirements for wind turbine gearboxes

IEC 61400-4:2012(E) is applicable to enclosed speed increasing gearboxes for horizontal axis wind turbine drivetrains with a power rating in excess of 500 kW. This standard applies to wind turbines installed onshore or offshore. It Standard provides guidance on the analysis of the wind turbine loads in relation to the design of the gear and gearbox elements. The gearing elements covered by this standard include such gears as spur, helical or double helical and their combinations in parallel and epicyclic arrangements in the main power path. The standard is based on gearbox designs using rolling element bearings. Also included is guidance on the engineering of shafts, shaft hub interfaces, bearings and the gear case structure in the development of a fully integrated design that meets the rigours of the operating conditions. Lubrication of the transmission is covered along with prototype and production testing. Finally, guidance is provided on the operation and maintenance of the gearbox.

Aérogénérateurs — Partie 4: Exigences de conception des boîtes de vitesses d'aérogénérateurs

General Information

• Status: Published
• Publication Date: 04-Dec-2012
• ICS: 21.200 - Gears
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: ISO/TC 60 - Gears
• Drafting Committee: ISO/TC 60 - Gears
• Current Stage: 9599 - Withdrawal of International Standard
• Due Date: 02-Apr-2025
• Completion Date: 02-Apr-2025

Relations

• Revised: IEC 61400-4 - Wind energy generation systems — Part 4: Design requirements for wind turbine gearboxes
• Effective Date: 06-Jun-2022
• Revises: ISO 81400-4:2005/Cor 1:2005 - Wind turbines — Part 4: Design and specification of gearboxes — Technical Corrigendum 1
• Effective Date: 15-Apr-2008
• Revises: ISO 81400-4:2005 - Wind turbines — Part 4: Design and specification of gearboxes
• Effective Date: 15-Apr-2008

Standards Content (Sample)

IEC 61400-4
Edition 1.0 2012-12
INTERNATIONAL
STANDARD
colour
inside
Wind turbines –
Part 4: Design requirements for wind turbine gearboxes

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IEC 61400-4
Edition 1.0 2012-12
INTERNATIONAL
STANDARD
colour
inside
Wind turbines –
Part 4: Design requirements for wind turbine gearboxes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XG
ICS 27.180 ISBN 978-2-83220-506-8

– 2 – 61400-4 © IEC:2012(E)
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms, definitions and conventions . 12
3.1 Terms and definitions . 12
3.2 Conventions . 15
4 Symbols, abbreviations and units . 17
4.1 Symbols and units . 17
4.2 Abbreviations . 21
5 Design for reliability . 23
5.1 Design lifetime and reliability . 23
5.2 Design process . 24
5.3 Documentation . 26
5.4 Quality plan . 26
6 Drivetrain operating conditions and loads . 27
6.1 Drivetrain description . 27
6.1.1 General . 27
6.1.2 Interface definition . 27
6.1.3 Specified requirements across interfaces. 28
6.2 Deriving drivetrain loads . 28
6.2.1 Wind turbine load simulation model . 28
6.2.2 Wind turbine load calculations . 29
6.2.3 Reliability of load assumptions . 29
6.3 Results from wind turbine load calculations . 29
6.3.1 General . 29
6.3.2 Time series . 30
6.3.3 Fatigue load . 30
6.3.4 Extreme loads . 31
6.4 Operating conditions . 31
6.4.1 General . 31
6.4.2 Environmental conditions . 31
6.4.3 Operating strategies . 32
6.5 Drivetrain analysis . 32
7 Gearbox design, rating, and manufacturing requirements . 32
7.1 Gearbox cooling . 32
7.2 Gears . 33
7.2.1 Gear reliability considerations. 33
7.2.2 Gear rating . 33
7.2.3 Load factors . 34
7.2.4 Gear materials . 36
7.2.5 Subsurface initiated fatigue . 37
7.2.6 Gear accuracy . 37
7.2.7 Gear manufacturing . 37
7.3 Bearings . 38
7.3.1 General . 38

61400-4 © IEC:2012(E) – 3 –
7.3.2 Bearing reliability considerations . 38
7.3.3 Bearing steel quality requirements . 39
7.3.4 General design considerations . 39
7.3.5 Bearing interface requirements . 42
7.3.6 Bearing design issues. 43
7.3.7 Bearing lubrication . 46
7.3.8 Rating calculations . 47
7.4 Shafts, keys, housing joints, splines and fasteners . 50
7.4.1 Shafts . 50
7.4.2 Shaft-hub connections . 50
7.4.3 Flexible splines . 51
7.4.4 Shaft seals . 51
7.4.5 Fasteners . 51
7.4.6 Circlips (snap rings) . 52
7.5 Structural elements . 52
7.5.1 Introduction . 52
7.5.2 Reliability considerations . 53
7.5.3 Deflection analysis . 53
7.5.4 Strength verification. 53
7.5.5 Static strength assessment . 54
7.5.6 Fatigue strength assessment . 58
7.5.7 Material tests . 62
7.5.8 Documentation . 63
7.6 Lubrication . 63
7.6.1 General considerations . 63
7.6.2 Type of lubricant . 64
7.6.3 Lubricant characteristics . 65
7.6.4 Method of lubrication . 66
7.6.5 Oil quantity . 67
7.6.6 Operating temperatures . 68
7.6.7 Temperature control . 68
7.6.8 Lubricant condition monitoring . 69
7.6.9 Lubricant cleanliness . 69
7.6.10 Lubricant filter . 70
7.6.11 Ports . 71
7.6.12 Oil level indicator . 71
7.6.13 Magnetic plugs . 71
7.6.14 Breather . 72
7.6.15 Flow sensor . 72
7.6.16 Serviceability . 72
8 Design verification . 72
8.1 General . 72
8.2 Test planning . 72
8.2.1 Identifying test criteria . 72
8.2.2 New designs or substantive changes . 73
8.2.3 Overall test plan . 73
8.2.4 Specific test plans . 73
8.3 Workshop prototype testing . 74
8.3.1 General . 74

– 4 – 61400-4 © IEC:2012(E)
8.3.2 Component testing . 74
8.3.3 Workshop testing of a prototype gearbox . 74
8.3.4 Lubrication system testing . 75
8.4 Field test .
...