Rotor having multiple permanent-magnet pieces in a cavity

A rotor for an electric machine includes a rotor core constructed of magnetically-permeable material. The rotor core may include a first cavity having a first curved end portion and a second cavity having a first curved end portion disposed adjacent the first curved end portion of the first cavity. The rotor may also include a permanent-magnet cluster. The permanent-magnet cluster may include a permanent-magnet layer that substantially magnetically isolates a portion of the rotor core disposed inside the permanent-magnet cluster from portions of the rotor core disposed outside the permanent-magnet cluster. The permanent-magnet layer may include one or more permanent-magnet pieces disposed in the first cavity and one or more permanent-magnet pieces disposed in the second cavity.