Gearboxes for wind turbines: reliability, availability, and maintainability

The gearbox, for example, is one of the main components of a wind turbine that is used in most utility-type turbines and, although not all wind turbine models incorporate this component, the prevailing design choices involve integrating gearboxes to increase the rotational speed, from the low-speed rotor to the high-speed electrical generator, optimizing, that way, energy conversion and efficiency. 

In the lifetime of a wind turbine, the gearbox will need to be repaired or refurbished several times. Depending on the capacity factor of the plant, environmental conditions, and other factors, a gearbox may have an interval between repairs/refurbishments of 5 to 8 years. Operators usually use data from similar wind turbines, inputs from the manufacturers, and online condition monitoring data to predict these maintenance needs, and plan accordingly. The goal for these critical components should be to increase the time between repairs. I.e., the reliability of the component while minimizing the unscheduled maintenance events, and planning the maintenance tasks in periods where energy production capacity is lower.

Another key concept is the availability of gearboxes in the aftermarket. Depending on the turbine and gearbox model, there will be more or fewer units available in the market, either via straight sale or exchange. Although the stocking strategies for these critical components depend on the characteristics of each operator and each project, what is true is that each day that a wind turbine is down, due to the unavailability of a gearbox, is a day that the turbine is not generating revenue. Indeed, having access to a broad network of suppliers that can supply the model you need, when you need it, is key to meet the production targets of a project.

Last but not least, comes the concept of maintainability, i.e. the ability to continuously improve the operation and maintenance of the gearbox, which has a direct impact on its efficiency and reliability. This relates to all kinds of product improvements that either the gearbox manufacturers or experienced service providers introduce, based on accumulated experience and know-how. It is very common to see upgrades becoming available with the most used gearboxes. Evaluating correctly and incorporating these, can have a big impact on the machine’s reliability and useful life.

By offering a wide range of solutions, Spares in Motion supports owners and operators in maintaining their turbines, with personalized solutions to attend to the complexity of main components, like the gearbox, during the wind turbine operational life. Together, with our independent network of trusted partners and suppliers, we provide repaired and refurbished components in the best possible conditions, taking care of quality, delivery, and warranty.