Repair and modification of wind turbines



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Stork Gears & Services is increasingly of service to clients from the wind energy sector with the repair and modification of wind turbines. The development of wind energy has been progressing over the years. The government has the goal that in 2020, 10% of all energy used in the Netherlands has to be environmentally sustainable. Via the so called MEP-regulation (Environmental quality of electricity production) the production of clean durable energy is encouraged. The important advantages of wind energy are clean energy production and less dependence on fossil energy sources.


Horizontal Axis Wind Turbines (HAWT), the most common of all wind turbines, have their main rotor shaft and generator at the top of a tower. From left to right of the picture there is a rotor, a low speed shaft, a gearbox, high speed shaft, generator and controller.

The rotational speed is low to let the generator produce the necessary 50 rounds per minute. Most windturbines have a gearbox which turns the slow rotation of the blades into a quicker rotation that is more suitable for generating electricity.


Through wearing of gear wheels and bearings the wind turbines cannot function optimally anymore. The repair and modification of wind turbines is a complex task because of the weight (32 tons) and height (± 50 meters). Stork Gears & Services was asked by an owner of seven wind mills to bring back the wind turbines to the original state by repair and modifications.   


The gearbox was a Jahnel Kestermann, type 2 CS500. The teeth and bearings were damaged and there was oil leakage. Using the assistance of a 700 ton crane the nacelle with the gearbox was transported to Stork Gears & Services. To reduce future repairs to a minimum, we also made some modifications in our engineering department. In this way we lengthen the lifetime and reliability and therefore availability.

1 Repair and modification of wind turbines