Superconducting magnetic energy storage system with low friction coil

Abstract

A superconducting magnetic energy (SMES) system having an axially sectioned multilayered solenoid coil immersed in a liquid helium bath contained in annular helium vessel includes as an interface between each section of the inner and outer layers of the coil and the helium vessel a finger plate assembly comprising a plurality of electrically nonconductive finger plates clamped at one end with spacers between adjacent finger plates to hanger plates welded to the helium vessel walls. The other ends of the finger plates are interleafed with the turns of the coil and clamped together with the coil turns by clamping assemblies which clamp the turns in adjacent layers of the coil. Loading bars between the layers transmit the radial loads generated by the magnetic and thermal forces acting on the coil to the finger plates. The radial loads pass through the finger plates to the helium vessel side walls and then through radial struts outside the helium vessel to the walls of a trench in which the SMES system is installed. Axial loads on the coil produced by the Lorentz force and differential thermal expansion and contraction of the coil relative to the helium vessel are absorbed in bending of the finger plates.