A review of wind turbine main-bearings: design, operation, modelling, damage mechanisms and fault detection

Abstract

Abstract. This paper presents a review of existing theory and practice relating to main-bearings for wind turbines. The mainbearing performs the critical role of supporting the turbine rotor, with replacements typically requiring its complete removal. The operational conditions and loading for wind turbine main-bearings deviate significantly from those of more conventional power plants and other bearings present in the wind turbine power-train, i.e. those in the gearbox and generator. This work seeks to thoroughly document current main-bearing theory in order to allow for appraisal of existing design and analysis practices, while also seeking to form a solid foundation for future research in this area. The most common main-bearing setups are presented along with standards for bearing selection and rating. Typical loads generated by a wind turbine rotor, and subsequently reacted at the main-bearing, are discussed. This is followed by the related tribological theories of lubrication, wear and associated failure mechanisms. Finally, existing techniques for bearing modeling, fault diagnosis and prognosis relevant to the main-bearing are presented.

Constructing Fast and Representative Analytical Models of Wind Turbine Main-Bearings

“…The bearings are modelled as single point fixed supports, meaning all loads are reacted by a reaction force at the MB with no moment reaction present. The two most common bearings used for WT MBs are spherical roller bearings (SRB) which cannot react moment loads and tapered roller bearings (TRB) which can react both forces and moments (Yagi, 2004;Smalley, 2015;Hart et al, 2019a). Therefore, the validity of existing models for different bearing types should be considered.…”