Search

REBCO coil is a promising technology for superconducting magnetic energy storage system (SMES). Although degradation has been discovered in epoxy impregnated coil, it is essential to fill the coil with epoxy in such occasion. This paper describes preparation of large scale epoxy impregnated REBCO coil for SMES. The coil with inner diameter 320 mm and 268 turns was tested at 77 K both before and after epoxy impregnation. Consistency of Ic value and high n-value suggest that there was no degradation in the coil. Conduction cooled test was also carried out. Transport current was run up to 223 A at 50 K.

In this paper, the natural vibration mode shapes and frequencies of the stator of large electric machine are computed by finite element method (FEM). In FEM model, several boundary treatments are especially considered, including welded connection between boards of stator, bolt connecting structure between end housing and frame board, shrink fitting between rotor axis and bearing. The influence of cooling system and rotor to the natural modes and frequencies of the stator is especially analyzed and discussed. By impact testing on the stator of a large electric machine, the main modal parameters including natural modes and frequencies of the stator are identified. It is verified that the FEM calculation of vibration modes and frequencies of the stator is valid by contrasting calculation result with experiment data.