Magnetic propulsion for magnetically levitated trains

✍ Scribed by P.H. Melville

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 186 KB
• Volume: 13
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(73)90186-0

✦ Synopsis

A lot of attention has been devoted recently to the possibilities of levitating high speed trains (up to 500 km h "1) by means of superconducting magnets. 1-8 Two systems are under consideration. The more complicated system, which was originally proposed by PoweU, 1 uses a track consisting of a series of short circuited loops of aluminium. The superconducting magnets moving with the train induce currents in these loops, thus providing a mutual repulsion. 1-4 In the simpler system proposed by Wipf, a continuous aluminium track serves the same purpose as the short circuited lopps. 5-9 The main advantages and disadvantages of the two systems are that the loop system has a much lower eddy current drag (about 1/10 of that of the sheet system), but requires larger magnets and thus more cryogenic equipment (about ten times that for the sheet system). 4 The eddy current drag in the sheet system is about equal to the air resistance, and thus some reduction of this would be a help, but reduction to 1/10 may not be worthwhile in view of the increased cost of cryogenic equipment, and the more complicated track required. However, in evacuated tunnels, particularly at very high speeds (up to 1 500 km h'l), the loop system comes into its own, and is certainly the more efficient.