Equilibrium dynamics and stability of null-flux, brake-flux, and double-track, normal-flux electrodynamic levitation systems

The three electrodynamic levitation (EDL) schemes most frequently suggested as alternatives to the normal-flux, single-track schemes are theoretically examined. The analysis concentrates on the null-flux design. Comments regarding the brake-flux and double-track, normal-flux schemes are made by analogy only. For the first time the zero-torque equilibrium of a system under the influence of an external driving force is considered. The often-used zero-pitch assumption is herein refuted. Lift, drag, and the lift-to-drag ratio as a function of the dynamic equilibrium suspension positions are calculated. The equilibrium equations of motion are expanded to include small perturbations and the resulting relations are then used to analyze the stability of the equilibrium suspension positions with regard to external disturbances. The new analysis shows that substantial heave mode supression is possible with the alternative systems. Throughout the analysis comparison is made with the normal-flux, single-track model characteristics.