The paper proposes a partly analytical and partly numerical method for evaluating the propulsion, levitation and lateral destabilizing forces in a levitated short rotor linear induction motor (LIM) considering the finite width of the stator and finite width and length of the rotor. The calculated forces at unity slip are compared with experimental results on a laboratory size model built for this purpose. Constructional details of the levitated LIM (LLIM) are also given. Method of lateral stabilization and its analysis are considered in Part II of the paper.