Loss analysis of multistranded twisted wires by using 3D-FEA simulation

The effect of the twisting on the losses of multistranded wires is investigated by means of the combination of a general purpose CAD tool and 3D-FEA simulation. The 3D simulation shows that at bundle level appears both skin and proximity effects which are not usually considered in 2D analyses. These effects generate extra losses in the cable which depend on the helix pitch and the isolation between strands. A loss model including these effects is not concluded from this study however, some manufacturing guidelines are pointed out. The results suggest that it is convenient to avoid small helix pitches and to increase the isolation between strands. Results of the 2D and 3D analysis and the loss model of isolated strands are compared.