Dynamic model for hydropower generators with floating rotor rim

•The model mixes stationary and rotating frames of reference.•It includes Centrifugal loads, Coriolis, and Electromagnetic effects.•Rotor/shaft connectors increase the natural frequencies and alter mode ordering.•Centrifugal forces affect the expansion of the rotor ring the most. For rotordynamic analysis of hydropower units, the generator is treated as a rotating rigid body. However, previous studies have confirmed that certain designs of generators are elastic, so the complex geometry of generators cannot be considered rigid. This work produced a model of hydropower generators with floating rotor rims, consisting of a rigid hub and a flexible rotor rim coupled with flexible connections. The model takes into account the influence of centrifugal and Coriolis effects, and the electromagnetic interaction between rotor and stator. The model also reproduces the dynamics of the generator with static and dynamic eccentricities. A generator prototype was employed to test the model, showing its different applications. Once validated by empirical data, this model could be used when designing generators.