A rotor (11) with a squirrel cage and permanent magnets (19) mounted on and distributed around the circumference of the rotor, including a core stack extending over the entire rotor region with longitudinally continuous rotor slots extending over the length of the core stack. The squirrel cage is constructed with cage bars disposed, and preferably cast, in the rotor slots; short circuit rings connect the cage bars at both end faces of the core; and the radius of the rotor region is reduced by at least the radial thickness of the magnets. The radius of rotor (11) is reduced over the entire length between short circuit rings (17) such that the radial height of cage bars (15, 29) or cage webs (27) connected thereto is reduced. Also an electric motor or a radial pump having such a rotor, and methods of producing or operating such devices.