First operation of a hoop energy storage system

A study of the design, fabrication and operational characteristics of a Hoop Energy Storage System (HESS) has been done. For the magnetic levitation of Nd-Fe-B permanent magnet, the magnetic force calculation and dynamic analysis of the rotational stability were included in the design and operation of HESS. 2564 Nd-Fe-B magnets which has the dimension of 2 in./spl times/2 in/spl times/1 in were assembled for the levitation of a 3.7 ton carbon fiber composite hoop. A computer simulation of rotation under magnetic force and torque due to both the vertical stabilization magnetic set and the radial stabilization magnet set showed that the rotation of the hoop's spin axis induced by the torque of the levitated rotor magnets reduces the additional active control. The fabrication of a 6 m-diameter carbon fiber composite hoop was completed and the ANSYS code was used to study its stress analysis. The study showed that the strength of the hoop material is high enough for the 600 MJ-energy storage. A performance test, of the HESS at a low speed rotation is reported.