Wind Turbine Bearing Failure
One of the major areas of failure in wind turbines involves contaminants damaging the bearings, which in turn compromises the performance of other components, results in less efficiency, and the potential for catastrophic failure. When you consider the outdoor, uncontrolled environments that wind turbines operate in, its easy to see why seals are the first line of defense for bearings.
Particulate Contamination Bearing Failure
There are a variety of bearing failures that can be traced back directly to particulate contamination. Bearing damage that takes place because of particulates getting in where they dont belong includes abrasive wear, bruising, and denting. While not all contamination takes place after installation (in fact, much of it can take place before), seals must be checked on a regular basis to make sure that they are providing protection and that lubrication levels are being maintained.
Outdoor Moisture Contamination
Moisture can be another form of contamination, and when you consider the fact that wind turbines operate outdoors, and some of them are operating offshore, this comes as no surprise. Moisture can cause etching of bearing surfaces, as well as corrosion. Again, the first line of defense is the seals.
Wind Turbine Gearbox Seals
In a wind turbine, the main area that suffers bearing failure due to contaminants tends to be the gearbox. The gearbox will usually have a labyrinth seal, but this should be backed up with an external deflector seal to make absolutely sure that outside contaminants cannot get in.
What causes the seals to fail? With the exception of seals splitting open (which can be due to incorrect installation and misalignments), the seal usually exhaust its useful life and wears out. The effects of temperature cycling, heat aging, ozone exposure, corrosive media, and inappropriate seal material choice can all contribute to a reduced seal life. However, the proper choice of a polymer seal can extend the life of the bearings by providing a more reliable, resilient seal.
In wind turbines, PTFE (polytetrafluoroethylene), TPU (thermoplastic polyurethane), and UHMW (ultra-high molecular weight polyethylene) are common choices for seal materials. These materials offer resistance to extrusion, wear resistance, extremely low friction, and performance under abrasive conditions, which is something that elastomeric seals cant always promise. This in turns means a longer seal life, and a more controlled, bearing-friendly environment.
Here are some additional articles on Polymer seals:
- Polymer Seals for Wind Energy Applications 101
- 7 Questions and Answers about Polymer Labyrinth Seals You Should Know
- PTFE Rotary Lip Seals – 6 Feature Competitors Dont Want You to Know!
An Execellent Alternative Wind Turbine Seal
If you are looking to extend the bearing life in a wind turbine, a good place to start is the seals. While elastomeric seals are commonly used, polymeric seals are an excellent alternative that can provide a longer seal life and better resistance to contamination.
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