A permanent magnet rotor for an electrical generator includes a rotor shaft and a rotor core mounted coaxially upon the rotor shaft. The rotor core defines a plurality of longitudinal core passages which include a segment of a rotor cooling circuit, and further includes a permanent magnet outer core component mounted on an inner core component and including a plurality of permanent magnets. A cooling liquid containment mechanism for the permanent magnet rotor includes a first liquid containment cover coupled to the inner core component and a second liquid containment cover coupled to the inner core component. The liquid containment covers are configured to contain cooling liquid passed from an inlet segment of the rotor cooling circuit defined by the rotor shaft into the plurality of longitudinal core passages, and thenceforth into an outlet segment of the rotor cooling circuit also defined by the rotor shaft. The liquid containment covers are mounted on the inner core component at locations radially inward of a cylindrical outer surface thereof.