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Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.

Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Alexander Kari Geislinger GmbH, Austria
Co-authors:
Alexander Kari (1) F Christof Sigle (1) Joerg Berroth (1)
(1) Geislinger GmbH, Hallwang, Austria (2) Center for Wind Power Drives, Aachen, Germany

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

Alexander Kari has been with Geislinger Dampers & Couplings since a year. He is Sales Manager for products to the big bore engine and marine industry and Product Manager for Wind Power. He holds a college degree in mechanical engineering as well a Master in International Business. His main role in Wind Power is to introduce Compowind®, a novel slow-speed coupling based on composite technology, to the market. Before joining Geislinger Alex has been with Miba Bearings for eight years. Aside of Sales duties to the big bore engine industry, his task was to develop and introduce alternative durable bearing


Poster

Poster Download poster (11.74 MB)

Abstract

THE EFFECT OF A FLEXIBLE SLOW-SPEED COUPLING ON THE DYNAMIC BEHAVIOUR OF A DRIVETRAIN

Introduction

Deficient drivetrain reliability still is one of the main goals to work towards in order to achieve competitive energy cost, especially concerning multi-megawatt wind turbines. In contrast to marine applications, in the wind industry the use of flexible couplings between the rotor and the gearbox is a rather new approach, but also a potential remedy to increase the robustness of drivetrains.

Approach

Drivetrain, gearbox and bearing experts have made every endeavor to increase the reliability of wind drivetrains. Many approaches to making the drivetrain more robust are restricted to simply increasing the load capacity of its components. By increasing size and weight, side-effects are inevitable and often result in pre-mature failures. Some experts are focusing on one of the core problems – the non-torque loads – and how to avoid its transmission to the entire drivetrain and its components.
This paper will show how a flexible coupling, made of advanced compound material, sufficiently reduces non-torque loads without adding unnecessary complexity to the drivetrain and maintaining the tower head mass.


Main body of abstract

Compowind® has been developed by Geislinger, and is based on more than 20 years’ experience in engineering and production of maintenance free, weight-saving couplings and shaft lines for advanced marine applications. Compared to standard technologies, the weight-saving design does not add unnecessary mass to the nacelle. Compowind® products are customized according to the requirements of the drivetrain and designed to last the wind turbine’s lifetime. The coupling does not contain any sliding or aging parts and provides almost linear, very low restoring forces. The Geislinger Compowind® coupling has been tested and validated in a dynamic test rig as well as on tower of a multi-megawatt offshore turbine.
For proper quantification of the effect of Compowind® in terms of reduction of non-torque loads, and therefore reducing gearbox and bearing loads, a full multi-body simulation of a real drivetrain, considering specific wind load cases with and without a flexible coupling, is necessary. To realize this, Geislinger teamed up with the Center of Wind Power Drives (CWD), a department of the RWTH Aachen University. CWD’s experts developed a multi-body simulation model of a generic 6MW wind turbine, suitable to integrate an elastic coupling. Axial, angular and bending stiffness as well as damping properties of the elastic coupling are considered to allow simulations in all six degrees of freedom.
Dynamic simulations take account of typical load cases such as turbulence, emergency-stop, grid failure, parking, trundle operation, and extreme gusts. A direct comparison of cut loads on defined interfaces of the wind turbine with standard configuration compared to the same wind turbine equipped with Compowind® facilitates determine the couplings’ influence on the dynamic behavior of the drivetrain.


Conclusion

Elastic couplings on the slow-speed side of a wind turbine possesses the ability to significantly reduce non-torque loads transmitted to the drivetrain. Geislinger Compowind® is the first coupling of its kind that does not add complexity and weight to the nacelle. For the first time it will be possible to present a pre-post comparison thanks to CWD’s generic 6MW model, which is contributing to important decision-making for future wind drivetrain layouts.


Learning objectives
This paper will show how the use of a multi-body simulation in a pre-post study is able to clearly quantify the significant load reducing effect of a slow-speed coupling and how carbon-fiber compound technology, derived from marine applications, enables a weight-saving and maintenance-free use of such a coupling in a multi-megawatt offshore wind turbine.