A rotor for a rotary electric machine, the rotor including first and second pole pieces each having a respective magnetic hub arranged for rotation about an axis along which they are spaced. Pluralities of magnetic first and second pole fingers are spaced from each other and extend between the hubs. Each pole finger has a proximal end connected to its respective hub, and an axially opposite distal end. The first and second pole fingers circumferentially alternate about the axis, and each pole finger has a respective radially inner surface defining a cavity that extends axially from the distal end to a cavity terminus. Relative to each pole finger, at a respective axial position between the distal end and the cavity terminus the radial distance between the axis and the radially inner surface is substantially greater inside of the cavity than outside of the cavity.