A DYNAMO-ELECTRIC MACHINE

摘要

A dynamo-electric machine, for example a marine propulsion unit, comprises a stator (14) and a rotor in the form of an impeller (4). The impeller (4) is rim-driven and comprises an annular core (10) of ferromagnetic material, on which are provided layers (16, 18, 20) in the form of an environmental enclosure (20) and electrically conductive sleeves (16, 18). Appropriate selection of the materials and thicknesses of the layers (16, 18, 20) enables the starting and normal running performance of the machine to be optimised.