Introduction to Modern Wind Turbines - Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering - page 56

Figure 2-8 (Concluded). Typical HAWT power trains. (b) Medium-scale: Vestas V27/225
kW ( Courtesy of Vestas Wind Systems A/S ) (c) Large-scale: Mod-5B/3.2 MW [Boeing 1988]
Turbine Shaft Assembly
The turbine shaft assembly is one of the most critical components in a HAWT, because
of its dual structural/mechanical function. Rotor weight, thrust, torque, and lateral forces all
cause fatigue loading on this component whose design lifetime usually equals or exceeds that
of the total system. The design, manufacture, installation, and maintenance of this assembly
must be of the highest quality in order to meet its dificult service requirements. In addition
to the primary shaft with its bearings, lubrication, and couplings, turbine shaft assemblies