According to the new standard, gearboxes must have a design lifetime similar to that of the wind turbine. For wind turbine classes I through III, this means 20 years.
The standard has been prepared by IEC TC 88 in cooperation with ISO TC 60: Gears. This first edition constitutes a technical revision of ISO 81400-4, which it cancels and replaces. The content has been extensively expanded and includes the following significant technical changes:
extension of the scope to wind turbines above 2 MW;
considerations for converging differing approaches to reliability in gear, bearing and wind turbine standards;
new clause on wind turbine loads specific to drivetrains;
new clause on testing and validation of new gearbox designs;
updated bearing selection tables for different locations in a wind turbine gearbox;
expanded design considerations on the use of bearings based on avoiding standard failures;
new clause on considerations and requirements in the design and analysis of gearboxes’ structural elements; and
updated considerations and requirements for lubricants and lubrication systems.