Improved design, longer operation

Rheine, 07.01.2011. Damage to the generator does not only result in an undesired downtime of the WTG and thus loss of revenue but can, depending on the type of damage, also cause considerable repair costs. In the worst case, the generator must be completely replaced, requiring a considerable investment.

In order to prevent major damage or total failure, Availon the world-wide leading provider of independent WTG services and SSB Duradrive GmbH have jointly developed a new generator for 2.0 MW Vestas® WTGs of type V66 VCS®, V80 and V90 and for 2.0 MW Gamesa® turbines of type G80 to G90. The generator has been certified by Germanischer Lloyd for the above mentioned WTG types on the basis of an expert report on the type test.

“With regards to the dimensions and design of the stator and rotor, the efficiency of the generator has been optimized”, explained Ulrich Schomakers, Managing Director of Availon.

For the layout of the type DALFI-1979 generator, suitable for different WTG makes, special emphasis was placed on an improved design and thus equally on a reliable operation and long service life. Special features of this new development include compatibility with generators of other manufacturers, a high rotational speed variability, optimized stator and rotor windings including heavy-duty insulation, greater protection of the roller bearing against bearing currents, optimized protection of the slip ring body against soiling and an efficient cooling concept.

The double-fed asynchronous generator thus allows the stator winding to switch from star to delta operation. This results in a considerable speed variability and thus optimum adaptation of the machine to existing wind conditions. In the star operation, the generator is loadable up to 1,000 kW and in the delta operation up to 2,000 kW.

The generator is dimensioned to comply with insulation class F. The machine can thus be constantly operated up to a maximum winding temperature of +155° C. Due to the use of extremely high-quality insulation materials (insulation class H) and the VPI process, the thermal stability of the generator is ensured up to a maximum winding temperature of +180° C, provided that certain constraints, such as maximum bearing temperature, are observed. As a result of the use of high-quality insulation materials, complying with insulation class H, the service life of the generator is increased even under demanding conditions, when used according to F.

Also during insulated installation of the roller bearings, considerable emphasis was placed on their reliability as well as cost efficiency. Due to their special design, the roller bearings feature an improved, insulated seat. This concept allows a reduction of subsequent costs, easy installation and repair and prevents destruction of the bearings by bearing currents.

The slip ring compartment is equipped with an external air extractor including filter, providing effective cooling and an efficient protection of the slip ring body against soiling. The risk of short-circuits and punctures as a result of considerable soiling has thus been reduced to a minimum.

As the cooling unit is driven by three separate external 3 kW asynchronous motors, optimum cooling is achieved even at partial load irrespective of the speed.

The new generator furthermore features multiple corrosion protection and a closed cooling system, making it also ideally suited for offshore use.

This upgrade is available as of immediately. For further information see www.availon.eu


"Vestas" and “VCS” are registered trademarks of Vestas Wind Systems A/S, DK. “Gamesa” is a registered trademark of Gamesa Corporacion Tecnologica, S.A., ES


Press contact:

Ms. Dagmar Hammudeh-Keil
Phone: +49 5971 8025-291
Email: dagmar.hammudeh-keil@availon.eu