Electromagnetism and mechanics are closely linked at a number of levels. Many electromagnetic problems are most easily visualised in terms of stresses and strains, and many mechanical devices such as bearings and clutches can be realised with electrical machines. In this talk I will describe a number of devices and problems to which a mechanical approach may contribute. On a microscopic level forces on superconductors are directly related to the pinning of flux lines. This provides a combination of a viscous and frictional force. If there is no pinning a force free configuration of vortices can form and the breakdown is similar to the buckling of tubes, although an unsolved problem. The magnetic pressure is B2 / μ0 and the new superconductors can produce about 3 T, corresponding to a pressure of about 100 MPa, so we can apply large forces. Since these can be applied across any non magnetic material we can make drives and clutches which work on sealed systems, which is useful for agressive chemicals, as well as the well known floating trains. A particular application which we have dveloped at the IRC is a magnetic bearing for a flywheel for energy storage. This pushes the technologies of carbon fibre composites, ferromagnets and superconductors to their limits as well as involving complex interactions between the rotational mechanics and the electromagnetism. The system will be desribed and it is hoped this will stimulate ideas for other applicatins of the technology.
