A rotor for an electrical machine has a rotor body and permanent magnets arranged on the circumference of the rotor body, wherein those areas of the circumference of the rotor body which are covered by the permanent magnets have at least one recess and/or that side of the permanent magnets which faces the circumference of the rotor body has at least one recess. Each recess is configured as a slot which extends in parallel relationship to a circumference-proximal side of the permanent magnets. Removably insertable in the recesses are ferromagnetic bars to allow removal of the permanent magnets.