Revolution – An industry paradigm shift?
We get asked this question often: How long should a gearbox last? There is no simple answer, as the reality is there are many site conditions beyond the owner’s control that have a major influence on this. In addition, although gearboxes are designed to run a theoretical 20 years given a certain set of site conditions, the original design and manufacture will have a major influence on life. Here are a few of the considerations outside of the owners’ control:
- Wind class
- Capacity factor
- Gearbox OEM
- Gearbox OEM material sourcing
- Gearbox OEM assembly practice
- Gearbox OEM load testing
Depending on the combination of these variables, within one site an owner will witness some gearboxes failing very early, while other gearboxes may run 20 or more years. Since few megawatt class turbines have been in operation a full 20 years, it is difficult to make a prediction on the average life. Based on our own practical gearbox experience, and what we have seen come through our facility, we speculate the median failure rate to be between 40-60% over the 20 year cycle.
We feel the more important question is: What will the life cycle costs be? This is where it is important to have a strong supply base that is engaged early on in your maintenance program. As an example, we do not often find that improper lubrication will cause a gearbox to fail prematurely, but rather escalate the repair costs when the gearbox fails as a result of one of the variables above that are outside of the owner’s control. In other words, contaminated lubrication, which an owner can influence, will cause irreparable damage to gearing even it if was not the failing component, it cannot be reused. The repair costs may vary by as much as 35%.
On the opposite end, knowing when to pull a gearbox is equally important to minimize removal and replacement costs. An owner may decide not to pull an early stage failure and run the gearbox through the balance of windy season so that it can be replaced the same time as other gearboxes that have completely failed.
So why is Revolution by Gearbox Express a paradigm shift for the industry? It is a technical product with a five year No-Risk warranty, and it has been designed to address as many of the premature failures modes as possible that are both within and outside of the owners control.
More importantly, it has shifted a portion of the risk back on to the owner’s supply chain. It is Gearbox Express’s belief that over time, best practices employed by Revolution will be learned and applied to other assets. It is a new way of thinking more than anything else – maximizing the life of this asset while minimizing the total life cycle costs.