Power generator assembly for rotating applications

A power generator assembly supplying electronics (power harvesting, sensors, wireless transmitter) mounted at 16c includes a rotating part 16a including multiple generator units 18a-18d, each unit including coil 20, two permanent magnets 22a, 22b and respective pole shoes/pole surfaces 24a-24b facing radially outward, ands a non-rotating part 16b including an arc-shaped ferromagnetic saddle adaptor 26 arranged with a radial distance to the pole surfaces 24a-24b, configured to close a magnetic circuit passing via the pole shoes 22a-22b through the coil in a rotational position where the saddle adaptor 26 overlaps the pole shoes 22a-22b. The rotating part is configured to be mounted on the end cap of a train axle bearing with the saddle mounted on the railway bogie side frame. Unbalance is corrected by a counterweight. Saddle may have a toothed profile to vary the air gap and may include additional pieces to increase saddle surface area and /or decrease the air gap. To avoid magnetic leakage in the magnetic open position the rotating part 16a further comprises additional permanent magnet 28a-28b arranged in proximity to said pole shoes of one of said multiple generator units 18a-18d (figs 3a-3b not shown).