This paper presents the design, simulation and experimental validation of a direct current linear actuator. The proposed actuator is similar in design with an electromagnet, but it uses Nd-Fe-B permanent magnets for producing a high holding force when it is in closed position. From this point of view, the main purpose of this paper is to analyze the working principle of the actuator and to explain the advantages obtained by using a special geometry of the magnetic circuit. Such a linear actuator can be used in electrical equipment, like high voltage vacuum circuit breakers. The proposed linear actuator ensures high force during closing, which is produced by a coil specially designed for this maneuver, and also a high force when the air gap is minimum, produced by Nd-Fe-B permanent magnets. The magnetic problem was solved using FEMM package, which has a specially designed LUA script incorporated in it. Mechanical parameters were determined with MATLAB program, by implementing numerical integration.

Keywords: Linear direct current actuator, Nd-Fe-B permanent magnets, High force, High holding force, High air gap, Ferromagnetic circuit, Numerical analysis, Specially designed coils