Assemblies and systems for contactless power and/or data transfer. The power transfer system includes at least a pair of opposing magnetic cores, each core having an L-shaped cross section. The data transfer system includes at least a pair of opposing stripline and/or microstrip conductors. Components for the power and/or data transfer system are preferably supported by a supporting surface in the rotor and/or stator. In some embodiments, the power and/or data transfer system is provided in a rotor flange and/or a stator flange for modularity.