1. Institute for Fundamentals and Theory in Electrical Engineering, Christian Doppler Laboratory for Multiphysical Simulation, Analysis and Design of Electrical Machines, Inffeldgasse 18, Graz A-8010, Austria e-mail:
2. Andritz Hydro GmbH, Dr.-Karl-Widdmann-Strasse 5, Weiz A-8160, Austria e-mail: