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.
Preliminary design studies of magnetic suspensions for high speed ground transportation. Final report on tasks 2/3, Feb 72--Mar 73
The report examines certain critical problem areas relative to magnetic suspension of high-speed vehicles and develops a baseline design for a TMLRV (tracked magnetically levitated research vehicle). Both types of magnetic suspension, the repulsive-force suspension and the attractive-force suspension, are considered. The present study has not turned up any problems serious enough to completely eliminate one of these competing suspensions. Areas considered in the report include propulsion systems and their compatibility with magnetically-levitated high-speed vehicles, aerodynamic effects, fairlure modes, studies of ride quality, and criteria for maximum allowable track roughness. In regard to the repulsive-force suspension, experiments have been carried out to measure ac loss in the superconducting magnets and an assessment of the magnetic shielding requirement has been made. Two model electromagnets for the attractive-force suspension, and their feedback control systems, were built and tested during the present study.
Measurement and Demonstration of Thermal Expansion Coefficient
There are many classroom demonstrations, such as the ball-and-ring experiment, for showing the existence of thermal expansion of solids. The coefficient of linear expansion α (= increase in length divided by the original length times the change in temperature) may be measured in high school laboratories using a number of methods.1–4 In this paper we describe an especially simple experiment for determining α for a metal rod. It is based on the well-known optical lever method and is suitable for either a laboratory experiment or a classroom exercise.