Review Lecture - Electromagnetic suspension and levitation techniques

Defying gravity seems to have fascinated scientists and philosophers through the ages. Electromagnetic suspension and levitation, following on from aircushion vehicles, such as the Tracked Hovercraft and the Aerotrain, has been the focus of attention and research for passenger-carrying vehicles since the 1970s. Two major demonstration systems are now in operation: one in Germany and one in Japan. Besides application to passenger-carrying vehicles, controlled DC electromagnet technology has been applied to produce frictionless magnetic bearings, conveyor systems, flow meters, etc. This is becoming a rapidly expanding area, moving out of the realms of academe into one of considerable industrial importance. The applications now include high-speed machine tool spindles, ultra-centrifuges, turbo-alternators, corrosive-liquid pumps, gas compressors and high-vacuum pumps, fly wheels for energy storage, handling components for protective coating and weighing balances. New developments in superconducting materials have also aroused fresh interest in the electrodynamic levitation schemes such as the Japanese one.