Finite element modelling of laminated structures in electrical machines

The investigation described in this paper shows that the losses in the stator cores of electrical machines are not necessarily dependent on radial/peripheral fluxes and that losses due to axial fluxes, although much smaller (4-5%) can still result in high loss intensity regions due to the concentration of loss. Segmentation of the core laminations also increases the axial losses by as much as 50%. This is principally due to the flux flowing axially in the vicinity of the butt joint and so results in higher localised eddy current losses in these regions. Finally, it is shown that the distribution of the axial flux in a laminated stack can be accurately modelled using a three region finite element model although further work is needed to logically derive some regions of permeability.