A procedure has been developed to generate a persistent current in superconducting rings. The basis of the method is a magnetic circuit made of a permanent neodymium-iron-boron magnet and an iron core; the current induced in the superconductor comes only from the energy of the permanent magnet avoiding the power supply. This device would allow the generation of current densities ≥105 A/cm2. Furthermore, an inductive method to reduce the persistent current circulating on the samples is also shown, the utilization of a simple iron core being its base. This method avoids possible damages when the critical temperature is exceeded with a high persistent current circulating.