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Tuesday, 11 March 2014
16:30 - 18:00 Advanced drive trains technologies
Hardware Technology  

Room: Tramuntana
Session description

In recent years several alternative drive train solutions have been proposed and also introduced on prototypes and in larger series. The new solutions seek to reduce the cost of energy by improving the reliability and service costs while keeping the initial costs competitive. Only a few of the new solutions have found their way into the competitive onshore market. The session will look into some of the potential incremental improvements that can be foreseen on the mainstream onshore market, but also look at some more radical concepts that may hold potential.

Learning objectives

  • Get an understanding of the options for journal bearings when used in the gearbox
  • See how field experience and numerical analysis can be used to optimise the performance of gearbox solutions
  • Learn more about the potential of magnetically geared solutions for wind application
  • See some of the potential improvements that can be implemented on drivetrains with gearboxes
Lead Session Chair:
Steffen Haslev Sørensen, RCA Engineering, Denmark

Andreas Reuter, Fraunhofer IWES
Gary Johnstone Romax Technology Ltd, United Kingdom
Gary Johnstone (1) F P
(1) Romax Technology Ltd, Nottingham, United Kingdom

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2014 and are published here unedited

Gary Johnstone has been working in the wind industry for the last 5 years and is currently a team leader in the drivetrain design and development group at Romax Technology. Prior to this he worked in powertrain research and development in the automotive industry for 8 years. He studied Automotive Engineering at Loughborough University followed by employment at Daewoo, Visteon and Controlled Power Technologies working on the development of powertrain technologies including hybrids, electric supercharging and exhaust energy recovery. At Romax Gary has worked on the development of new wind turbine drivetrain designs from 1.5MW to 10MW.



Reducing the cost, mass, package space & complexity of wind turbine drivetrains combined with a move towards medium speed is leading to increased integration of the generator & gearbox.

Traditionally the generator is designed independently from the gearbox and the opportunity for system optimisation and detailed understanding of system interactions is limited. System issues may not appear until drivetrain or turbine level testing is started. However it can be very expensive to fix at this stage.

This presentation introduces the advanced methods developed by Romax to identify potential electro-mechanical drivetrain issues much earlier in the design process.


The presentation will cover the following main topics:
• What can go wrong?
o Examples of Romax practical experience in drivetrain failures.
• Improved design method
o What can the wind industry learn from other industries?
o Electro-mechanical system design approach from concept through to detailed. What is important? How do you consider it? At what stage of the design process?
• How can we apply this method to the next generation wind turbine drivetrains?

Main body of abstract

What can go wrong?
Introduction to issues with existing wind turbine drivetrain designs potentially due to limitations in the design approach.
Improved design method
A comparison of a typical existing design approach and an improved approach from Romax. This includes how we can consider many thousands of drivetrain designs in the early product definition and concept phase through to detailed static and dynamic analysis of the generator and gearbox as a combined electro-mechanical system.
How can we apply this method to the next generation wind turbine drivetrains?
The application of this method to different medium speed drivetrain layouts is demonstrated. This highlights some fundamental differences in behaviour such as the sensitivity in performance to changing parameters such as manufacturing tolerance and bearing clearance. For example the unbalanced magnetic pull in a generator can have a significant effect on the bearing life. The gear and bearing performance of some drivetrain layouts are extremely sensitive to manufacturing tolerance and bearing clearance whereas others are far more robust. This method enables us to select the optimum concept and to understand the system behaviour early enough in the design process to address issues before prototype build and test.


Using the proposed methods we have demonstrated how many thousands of potential electro-mechanical drivetrain designs can be considered in the concept phase enabling an improved level of concept optimisation. We can now identify potential electro-mechanical system failure modes for different layouts at a very early stage in the design process. This enables a reduction in the cost and lead time of a new drivetrain developments.

Learning objectives
How to capture the interactions between the gearbox and generator to resolve potential failure modes early in the design process and reduce the risk of issues during testing and series production.