As part of the standard validation and certification process for its turbines in the Delta4000 series, the Nordex Group replaced the gearboxes first mounted in two N149/4.0-4.5 turbines in Wennerstorf, Lower Saxony, Germany.
The turbines installed at this site in 2018 are the world’s first Delta4000 turbines of this model.
The turbines have been in service since August and November 2018 respectively and are subject to a thorough evaluation of their condition within the first 15 and 24 months of operation. To this end, the manufacturer expertly disassembles the gearboxes into all parts in order to carry out a trained evaluation with the bearing suppliers and Nordex experts.
The objective is to ensure theoretically defined reliability and to integrate early results from the operation of the gearboxes into the series production and further development of more than 4MW rated power wind turbines.
In addition, the Nordex Group shall obtain relevant information verifying the design of the gearbox and optimizing maintenance. The drive train is constructed in such a way that it is possible to mount gearboxes from different manufacturers.
These planned gearbox exchanges offer the Nordex Group the opportunity to install gearboxes from different manufacturers and to test and compare their performance and efficiency in real service.
In the Wennerstorf wind farm, the first turbine gearbox was replaced in February 2020 and the second one in the adjacent turbine was replaced as scheduled in September.
It was the second time that the so-called self-hoisting crane (SHC), which is mounted on the turbine nacelle, was used to swap 4 MW+ gearboxes. This self-hoisting crane climbs up the turbine tower on its own turbine rope and positions itself on the top of the nacelle.
This means that it can be deployed easily, needs less room on the ground and is less costly to use. This solution has an advantage over traditional cranes, particularly in remote areas, for turbines with very high towers or in countries where the cost of the cranes is generally high.