Doubly-fed fan ge、ar oil viscosity viscosity common sense

Author: Zhang Wei (Petrolube sent through China)

As the blood inside the gearbox of the doubly-fed wind turbine, the gear oil plays the role of circulating lubrication, anti-wear, anti-rust, cooling and cleaning, and the most important indicator of gear oil: the meaning of kinematic viscosity is often Neglect. At present, the viscosity of the gearbox oil in the wind power industry is more conventional than that of the main gearbox, and the gear oil of No. 320 is selected for the main gearbox, and the gear oil of No. 150 or No. 220 is selected for the pitch and yaw drive reducer. Here, No. 320, No. 150 or No. 220 refers to the Kinetic Viscosity of the gear oil at 40 degrees Celsius, that is, the ratio of the dynamic viscosity of the oil body to the density of the oil body at the same temperature and pressure. According to the International System of Units SI, its unit is mm2/s square millimeters per second. According to the physical unit system CGS, its unit is cSt centistokes. Generally, the higher the kinematic viscosity, the more suitable the lubrication between the friction pair with high load and low rotation speed. But in fact, the kinematic viscosity of the gear oil is an indicator that is less stable and has a higher probability of change, even if the same batch of the same type of gear oil produced by the same brand of oil produces a 40 ° C motion viscosity deviation. 10% is also within the normal range, not to mention the viscosity changes geometrically with temperature, and no oil can guarantee that its kinematic viscosity will remain stable. For wind turbines with a warranty period of up to 7 years, how can we minimize the possible risk of reducing the kinematic viscosity of gear oils to the fan gearbox after long-term use? There are five suggestions below for reference.
1. When selecting the initial gear oil, please choose the gear oil with a relatively high viscosity index (not recommended to be less than 140). The higher the VI viscosity index, the more stable the oil viscosity is in the case of high and low temperature changes. The effect of small external temperature changes on the kinematic viscosity of new oil bodies;
2. Pay attention to regularly monitor the pH value and kinematic viscosity during the use of gear oil. Generally speaking, under the same temperature and pressure conditions, the kinematic viscosity will decrease with the increase of the oil use time. The viscosity reduction will generally be accompanied by the decrease of the additive content, the increase of the acid value and other indicators, and the need for synthesis. Consideration
3. When the gear oil is used for a long time (more than three years), if there is normal consumption and needs to be properly added, it can be based on the three factors of air pressure, temperature, gear oil usage time and replenishment, combined with real-time oil viscosity viscosity monitoring. As a result, the new gear oil with a higher viscosity grade is appropriately added;
4. When it is necessary to replace the new gear oil, it is necessary to use a proper amount of gearbox cleaning agent to provide sufficient gearbox cleaning to minimize the interference of the impurities of the old gear oil and the free acid-base deposit on the kinematic viscosity of the newly added gear oil. ;
5. In the cold season or extremely cold area, before the fan gear oil is refilled or replaced, try to reheat the new gear oil to 15 to 20 degrees Celsius, and try to avoid long-term outdoor storage.
In short, the kinematic viscosity of the gear oil is constantly changing, so don't hold the wrong idea of the selected oil viscosity. Considering the three important factors of temperature, air pressure and oil usage time, the impact of the viscosity of the oil, your gear oil can run longer, better to protect your fan gearbox.