The continuously increasing requirements placed on gearboxes demand more power and efficiency as well as a longer service life for all components. Modern high-performance gear oils make a decisive contribution to this. Lubricants are already included as an important element in the design of a gear unit. When developing a gear oil, a multitude of challenges must be taken into account: smaller oil volumes, higher temperatures, significantly better surface qualities of gears and bearings, longer service lives and increasing loads. In addition, there are extreme operating parameters, depending on the application. When used in wind turbines, for example, the highest loads, which vary frequently and over a wide range depending on changing wind forces, vibrations, fluctuating ambient temperatures and humidity are on the agenda, especially in offshore plants. The lubricants used should meet the most varied requirements and at the same time ensure the greatest possible performance, maximum operational reliability as well as flexibility and long-term use. An additional increase in energy efficiency is another decisive plus point that is becoming more and more important.
The formulation of a high-performance gear oil is a special challenge for every lubricant manufacturer. The manufacturers of gears and rolling bearings formulate strict requirements for the lubricants used and demand extensive suitability and compatibility tests for approval. It is important to select the optimally suitable base oils and combine an additive package which gives the lubricant all the desired properties. While the base oil mainly influences properties such as operating temperature and coefficients of friction, carefully selected additives provide protection against high loads and wear, anti-foam properties or reliable oxidation stability.
The required performance certificates are reliably met or exceeded by the carefully formulated high-performance gear oils of the ADDINOL Eco Gear series and the oils have numerous approvals from renowned manufacturers. The proven high-performance gear oils of the ADDINOL Eco Gear series prove their high performance reserve in tests and also in practice. The stable combination of antioxidants significantly slows down the aging process, and with good care, a service life of 7 to 10 years can be achieved. But even high-quality oils are subject to an ageing process in practice and cannot be used indefinitely. In addition to ageing products resulting from high stresses, dirt particles, dust and moisture also enter the system. For this reason, it is important to combine the use of high-performance lubricants with modern filter systems in modern wind turbines. Thanks to high-performance filtration with a high degree of separation, the outstanding properties of ADDINOL Eco Gear oils are decisively supported.
Powerful filter systems
The filter systems used in wind turbines must also be comprehensively tested and approved. This is the only way to ensure the technical functionality of a wind turbine from the outset and over a long period of time (> 20 years).
A prerequisite for the successful use of filter systems is the filterability of the lubricant used. In order to check the function, suitability and compatibility of filter and lubricant, filterability tests are carried out. Here the ADDINOL Eco Gear gear oils achieve best values and are accordingly approved by the five most important filter and pump system OEMs (see appendix).– HYDAC
The cleanliness classes of the lubricants used are defined by gear and system manufacturers and should be monitored on the basis of regular oil analyses. Rolling bearing manufacturers generally require particle sizes of ≤ 4 µm.
The filter systems used today consist of two filter units: A main flow filter (10 – 20 µm) is used in combination with a fine bypass filter (3 – 5 µm) according to the manufacturer’s requirements. The bypass filter is characterized by limited pressure and flow rate. Filter refinements smaller than 3 µm require a very high effort or a very large design in wind turbines and are therefore hardly feasible or impracticable.
In addition, an especially fine filter does not make a good one out of a bad gear oil!