Wind turbines are undoubtedly fantastic technology, which can help to cut costs and take the pressure off the environment, but sometimes they run into problems. One of the most common issues reported with wind turbines is that their yaw drive systems (which keep the rotor facing windward) can start to become very noisy.
Many wind turbine owners become concerned when their turbines start to produce an excessive amount of noise, and understandably, they want to sort out the problem as quickly as possible. However, unusual noises made by wind turbines are merely a sign that there is a problem within the wind turbine – they are not a problem in themselves. For this reason, it is important that technicians thoroughly investigate the source of the noise, so that they stand a good chance of finding the actual cause, rather than assuming that a good lubricant will always solve the problem.
If the noise being generated by the wind turbine is being caused by a mechanical issue, such as a very worn bearing, or misalignment, then changing to a new brand of grease, or varying the amount of grease used in the turbine, will have absolutely no effect on the issue.
It is also worth considering the manner in which grease is transported to the yaw bearings. It could be the case that the bearings are not getting enough grease because of the low speed and heavy load application, or the manner in which it is being greased. By changing these things, the problem might be rectified.
If, after a full investigation, you can find no other faults, then there is a good chance that poor lubrication is to blame, and the use of the thickener grease should be looked at. Thickener (diurea) grease is not the oil it is combined with, but merely the thickener aspect of the fluid. Lubrication to the bearing system is provided by the base oil and its additives, so it is important to establish the optimum level of viscosity if you want your machinery to work without issue.
You can then purchase an oil, preferably from a reputable brand like Fuchs or Q8, which will work at optimum levels, and which can perform well under extreme conditions. If, once you have started using a new lubricant that fits the turbine’s parameters perfectly, you continue to experience noise, then you will need to look at the mechanics again, as this is the most likely source of the problem.