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FEATURE SPONSOR


OILS & LUBRICANTS


Klübersynth GEM 4-320 N from Klüber Lubrication covers a wide temperature range without VI improvers.


KEEPING THE BEARING ROLLING The characteristics of a lubricating grease change depending on the load and temperature conditions. Wind turbine bearings are often operated at very low operating temperatures, sometimes even below the base oil's pour point, which may therefore


Operators of wind power stations should use synthetic gear oils with a high viscosity index (VI) exclusively to ensure the load- carrying capacity of the oil is sufficient during cold starts and to cover a wide temperature range.


affect functionality. The generator and main bearings of a wind turbine can heat up during operation; however the exposed pitch bearings are subject to low temperatures, almost the same as the ambient temperature.


SNR-FEB 2 rolling bearing grease test results


The anti-wear behaviour of lubricating greases in rolling bearings subject to small oscillating rolling and sliding motion can be determined on the SNR FEB 2 rolling bearing grease tester, or "false Brinell test" as it is also known since the wear pattern resembles the indentation caused in the Brinell hardness test.


In this test an axial load of 8000 N is applied, corresponding to a Hertzian pressure of 2100 N/mm2, with a frequency of 24 Hz and oscillating ± 3° angle with a test duration of 5 or 50hours.


Klüberplex BEM 41-141 was tested at ambient temperatures, resulting in less than 5mg of wear, and at -20°C, resulting in less than 20mg – both excellent values, which many other lubricants on the market do not attain.


…and whatever the application


COMPETITOR PRODUCT 1: Wear limits were exceeded so test had to be stopped after 13.5 hours.


Temperature behaviour depends on the base oil used, which is why viscosity index improvers are often used to increase a base oil's viscosity index, however VI improvers in gear oils have their disadvantages, with the polymers used becoming sheared over time, leading to viscosity loss and reduced load-carrying capacity.


COMPETITOR PRODUCT 2: Wear limits were exceeded so test had to be stopped after 39.6 hours.


If the temperature sinks below the lower service temperature of the grease, the grease stiffens, however it should still be soft and adhesive ensuring that the grease is not displaced and maintains a good lubricating effect.


KLÜBERPLEX BEM 41-141: Attained maximum run-time of 50 hours.


Klüber Lubrication Click to view more info


www.windenergynetwork.co.uk


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