Solar Electric Motor on Superconducting Bearings: Design and Tests in Liquid Nitrogen

The concept of the motor, described here, has been presented for the first time in 1959. It allows us to convert light energy into mechanical energy, without the need of any brushes or other power electronics. An original improvement that we have made to this structure concerns the superconducting suspension which tends to limit frictions and ensures natural stability of the rotor. The second major novelty is that we have designed the entire motor for operating in liquid nitrogen. The motor structure is detailed in this paper, including the electromagnetic design, the electrical and mechanical equations. Two different configurations of superconducting bearings are studied in order to make levitate the rotors. Finally, for the designed motors, only 10% of the installed onboard power is converted into mechanical power. All the experimental results, especially the speed of the motor, are consistent with the estimated values by the model.