The rotating subsystem is a key part of a wind turbine and, on the other hand, it is the most problematic to be modelled, where flexible beams are transformed in an assembly of rigid bodies connected by joints and spring-damper devices. Models are then classified by the number of masses considered. Several simplifications are assumed and some abstraction processes are applied in order to derive a dynamic model for control. The models are presented in an increasing degree of complexity. Thus, the user can select the model according to the control problem in the study. A simulation example illustrates the characteristics of the different models including poles and natural frequencies and execution time.