Safe conversion with oil analyses
A wind turbine filled with mineral oil-based gear oil is primarily converted to the new synthetic gear oil when maintenance or a regular oil change is due. However, if irregular values are found for a gear oil during a half-yearly OIL CHECK, the turbine can certainly be converted to synthetic oil early. This is particularly the case where the lubricant has aged prematurely and oxidation and additive degeneration, amongst other things, are seen on the IR spectrum.
Selected service companies that also perform maintenance on turbines in various wind farms carry out the conversion to the new synthetic gear oil. They carry out the work precisely to the specifications of Nordex. After draining the used oil at operating temperature, the gearbox and the cooling circuit for the oil is thoroughly rinsed. The oil that is not drained into reservoirs in bearings and ribbing is sucked out using special lances. The fresh synthetic oil then used to fill the turbine should not contain any more than 3% of the old mineral oil. Synthetic oil can also only perform to its maximum potential if it is unmixed. On the other hand, the more powerful cleaning effect of the synthetic oil could dissolve any sludge deposits that the mineral oil could not remove. However, if these sludge deposits do enter the overall lubrication system with the oil, the filters will be able to block them more quickly. In a worst case scenario, the lubricant supply lines in the bearings can be blocked by deposits, causing bearing failures and then gear damage.
So that operators are absolutely on the safe side, Nordex requires written proof in the form of a laboratory report that the requirement of less than 3% residual oil has been adhered to when the oil is changed. This is easy to do using the analysis sets designed by OELCHECK specifically for Nordex wind turbines. The proven Nordex analysis sets have been a permanent fixture in our maintenance concept for years. Before a turbine converted to the new synthetic gear oil re-enters operation, a "zero sample" is sent to OELCHECK. For this, "Oil change" is simply ticked on the shipping note.
Then, in the OELCHECK laboratory, values such as viscosity, wear, impurities and additives are determined, but not only these. As well as specific wave number ranges in the IR spectrum, the residual content of the previously used product in the fresh oil can also be determined precisely, amongst other things, by using its density. If it is under the limit of 3% and everything else is in order, the go-ahead is given for the further operation of the Nordex wind turbine, which will be more efficient thanks to the new synthetic gear oil.
Nordex – We’ve got the power
Nordex, with its headquarters in Hamburg and its main production site in Rostock, is one of the world’s leading manufacturers of on-shore wind turbines. The company’s areas of expertise include developing and manufacturing wind turbines, constructing ready to use wind farms and maintenance and service. With its Delta generation, Nordex is offering the fourth generation of its proven multi-megawatt platform. With larger rotors, an increased power rating and optimised technical systems, the Delta generation sets new standards in terms of cost, reliability, ease of service and work safety.