Propulsion Requirements for High-Speed Vehicles with Electrodynamic Suspension
The thrust force and power requirements for the propulsion of a vehicle with electrodynamic suspension (i.e., using superconducting magnets) are discussed. Acceleration thrust, magnetic drag, and aerodynamic drag are shown to lead to calculated power requirements of 8.0 MW under acceleration, and 5.2 MW for cruising at 300 mi/h. Aerodynamic and magnetic drag forces together produce acceptable passive deceleration characteristics. Propulsion requirements under normal operation and in emergency situations (i.e., unscheduled stops) are described. Propulsion systems are discussed, and it is concluded that the linear synchronous motor is most suitable for the proposed Maglev vehicle.
Electromagnetic Levitation
AN exhibit which has proved attractive at the Centennial Exhibition of the Dominion of New Zealand is showing an aluminium plate floating in air in a strong alternating-current field and frying eggs in a pan without visible means of heating and support. An iron core is concealed beneath a table top and excited by A.C. windings so arranged and connected that they produce alternating magnetic fields, toroidal in form, of high intensity and opposite polarity. An aluminium pan floats on this field with such definition of position that considerable effort is required to move it downwards or sideways. Heat generated in the pan, by currents induced by the field, does the cooking. It is very suitable as an exhibit for publicity purposes, but at present it does not look as if it has any practical application, as a very large electrical input is required to maintain a magnetic field of suitable form and intensity.
Canadian developments in superconducting Maglev and linear synchronous motors
Abstract Canadian developments in the application of superconducting magnets for levitation, synchronous propulsion, and guidance of high speed inter-city ground transport are described. At 480 km h −1 a 100 passenger vehicle weighing 300 kN is levitated 15 cm clear of a flat guideway (minimizing ice and snow accumulation) by eight 3.85 × 10 5 ampere-turns 100 × 30 cm magnets interacting with eddy currents induced in two 80 × 1 cm aluminium strips. The variable speed LSM uses fifty 5 × 10 5 ampere-turns 40 × 150 cm magnets interacting with split three-phase windings energized in 5 km sections and phase angle controlled to give 72% efficiency and 0.82 power factor. A lateral restoring force of 10 4 N cm −1 is produced by the propulsion magnets interacting with the levitation strip edges and with flat null-flux loops overlying the LSM windings. A review of cryogenic systems indicates that isochoric dewar operation is best suited for Maglev vehicles. The test facility, using stationary full-scale superconducting magnets and guideway components mounted on a 100 km h −1 vertical axis 7.6 m diameter wheel, is now fully operational and LSM tests are being performed.