Wind Turbines

From the beginning of commercial wind power in the mid-eighties until today the wind turbine technology won tremendous progress, which is , among other things, reflected in the turbine's size.

The production of rotor blades for modern wind turbines is nowadays - in terms of the processed mass - one of the largest long-fiber-reinforced industrial application areas. With the exception of a few particular cases rotor blades have been created of UP matrix systems. In recent years they were replaced increasingly by EP matrix systems. Another clear trend that occurred in the recent past is to use prepreg fibers and vacuum infusion technologies instead of hand-laminating. The reasons for this include the desire for consistent quality of the rotor blades as well as for an economic process.

Since late 2000, our company is indirectly involved in the production of rotor blades of the GE Wind Energy GmbH. Rotor blade shear webs of given rotor blade can be manufactured in forms that were prepared by AEROCONCEPT GmbH segment by segment as resin infusion process. But our main service in this area is the maintenance and repair of rotor blades.

Damaged blades

Main causes of damage are, in addition to design- and manufacturing-defects, overload, atmospheric conditions and poor maintenance.
The possible range of damage differs in many ways: Corrosion of the flange, erosion at the rotor blade leading edge, UV damage at the surface, structural cracks in the leading and trailing edges, shearing off of bonds in the blade interior, capital structure damages due to lightning or extreme ice accretion, fire due to faulty or non-existent functionality of the lightning protection system, worn out bearings any many other. The financial consequences could be kept low by regular maintenance.

Unplanned maintenance

Based on years of experience in the repair of aircraft structures made of fiber composite plastics, we succeeded in 1996, by repairing a 65 meter rotor of a 1.5 MW prototype turbine of the Tacke Wind GmbH, to develop the area of maintenance of wind turbine rotor blades.
As part of our service contracts with Enron Wind GmbH and General Electric Wind Energy GmbH we have checked and repaired hundreds of rotors of the 150 kW, 300 kW, 600 kW, 750 kW, 1.5 MW, 2.3 MW, 2.5 MW, 3.2 MW and 3.6 MW class for mounted and dismounted rotors.

Particular difficulties arise whenever repairs have to be carried out at the mounted rotor in high altitudes. Based on the not or only partially predictable weather conditions, such work is not planable to a greater extend. Moreover, the extent of damage when arriving at a wind turbine is generally not known.

The professional competence and high motivation of our employees so far, however, has been the guarantor for the most difficult tasks in the area of unplanned repair to be successful.

As a proof of quality and efficiency of our company stands the fact that AEROCONCEPT Gmbh is the first external service provider for rotor blade maintenance contracted by GE Wind Energy GmbH.

Scheduled maintenance

In case rotor blades are so severely damaged that a mounted repair is technically impossible or uneconomical, the affected blades are replaced by spare blades for the duration of the repair. Scheduled repairs and maintenance are carried out in our workshop.
This provides optimum conditions to make structural reinforcements in high stress areas as well as for the general overhauling of the blades.

Long-term experience gives evidence that rotor blades maintained or overhauled by AEROCONCEPT GmbH do not again develop structural damage.