The use of auxiliary technological equipment based on electromagnetic devices for the solution of a task a for the mechanization and automatic control of loading and unloading works at electric machines industry plants is considered. The mechanized loading of transformer plates into a furnace for annealing with the use of a developed electromagnetic set-point device for plates, based on roller linear induction motors (LIM) is given in an example. To define more exactly basic physics processes occurring in LIM and to justify their calculated models magnetic fields in a motor have been investigated experimentally. It is shown that the calculation of magnetic flows, secondary currents and inductor currents is reduced to the solution of equations describing the magnetic substitution circuit and of equations for determining the electric state of an inductor and a secondary element.