Solutions in the test field "alpha ventus"

AREVA Wind received via its Condition Monitoring System in May of this year a report on a temperature rise of bearing slides in two 5 MW wind energy mills which have been installed in the test field "alpha ventus" in the summer of 2009. The two concerned mills were shut down for safety reason. The six AREVA wind turbines generated more than 60 Mio. kWh by the end of March.

Some of these machines produced an energy output of approx. 14,5 Mio. kWh in the first eight months; that relates to 4300 full load hours per year. The cause analysis for the temperature increase, carried out in cooperation with the gear supplier Renk, subsidiary company of MAN Group, and independent institutes has immediately been introduced. The result of the technical analyses show as exclusive reason that the thermal expansion coefficient of the chosen bearing material in axial direction was not sufficiently considered in the bearing play. By the depleted bearing play an increased abrasion occurs at the bearing slides. No gear damage is on hand and the construction of the M5000 is in principle confirmed. Immediate and effective correction measurements have been taken in coordination with the customer and the gear supplier. The efficiency of the construction is confirmed by the good results of a gear inspection carried out in 2009 on the first prototype, which is in operation since 2004.

For any further gear, delivered to AREVA Wind, RENK applies the original bearing material, which has successfully been utilized in the prototypes for many years. RENK AG developed for AREVA Wind as of 2000 the integrated propulsion unit for the M5000. RENK delivers all pre-assembled gear modules to AREVA Wind, where they are installed in the nacelle units.

To secure a perfect quality in the future, AREVA will invest on a test facility in Bremerhaven. By this test facility, which shall be completed until 2011, AREVA Wind is setting new measures in the wind branch: The wind mills will then be tested already onshore under full load conditions. Experience made in the small test field "alpha ventus" and the investments in the test facility are important preconditions for a successful running of the next large projects. The exchange of the nacelles will be made in the late summer of 2010. In doing so Areva Wind will be fully supported by its parent company AREVA.