The generator is, in addition to generating electricity, used for control and starter for the turbine. The turbine is not self-starting but when the turbine has reached a sufficiently high rotation speed the wind can drive the turbine. The energy spent in the start sequence corresponds approximately to the energy generated for 3 seconds nominal operation.
For a variable speed turbine, it is important that the generator has a high efficiency over a wide range of rotational speeds. The possibility for this has been examined for the 225 kW generator designed, constructed and installed in Falkenberg. The generator has a minimum efficiency of 96% at wind speeds of 6.5 m/s. The generator has the task of controlling the rotation of the turbine for optimal efficiency but also to act as a brake at very high wind speeds.
For more information on generator physics, please contact Sandra Eriksson.