Shape Deviations in Hydropower Generators

I want to take the opportunity to thank my supervisor Jan-Olov Aidanpää, thanks for your supervision, your great interest in this work and for intro-ducing me to the theory of rotordynamics. I would also like to thank Thommy Karlsson, Rolf Gustavsson, Magnus Karlberg, Martin Karlsson, Mattias Lundström and Anders Angantyr for all interesting discussions regarding rotordynamics and hydropower machines. Thanks to Ludvig Lundström and Richard Perers for discussions about elec-tro magnetic forces. Finally Elforsk AB and the Swedish Energy Authority by the Elektra research program are acknowledged for the financial support of this project. Earlier measurements on hydropower generators have indicated the existence of backward whirling motion, and, also relatively large shape deviations in both the rotor and the stator. These non-symmetric geometries produce an attraction force between the rotor and the stator, called unbalanced magneti