## 2 Large Linear Electromagnetic Actuator (LLEA)  
This two-part research project was conducted towards designing, building, and testing the performance of a large linear electromagnetic actuator (LLEA). The data regarding its intended use, electrical circuit design, and performance were published before by the other research partner, Zeleros (Spain) [5, 6, 7], so only a brief description will be given here. This communication-type article focuses solely on the manufacturing technology challenges for such large actuators, as carried out by the first research partner, Magneto (Poland), and for this reason the technical details such as performance, losses, efficiency, etc., are not discussed hereinbelow. The LLEA was aimed at providing a more sustainable mode of transport within the port for standard shipping containers, which are large and heavy objects with a length of up to 12 m and a weight of up to 30 tons (freight forwarding). In this particular solution, the vertical weight of these shipping containers was to be supported on a railway-like wheeled system, but the total linear thrust was provided by the LLEA. The prototype was planned and designed to be up to 60 m long for the purpose of assessing its acceleration and deceleration capabilities so that a realistic practical weight-under-test could be accelerated to the required speed, as well as decelerated solely with electromagnetic means, safely over the whole length of the test track [5, 6, 7]. Due to the practical length limitations, the magnetic core was designed to be modular. This was mostly dictated by the practicality of several technological limitations as discussed in the following sections, such as the lamination stamping, the required assembly on-site, the transport issues, etc. This is because the final prototype was tested at the Port of Valencia in Spain, but the laminations were manufactured in Czestochowa, Poland, so up to 29 tons of magnetic core would have to be shipped between the two countries. Because of the sheer volume of the required magnetic material, the cost of the laminations proved to be a rather important factor. For this reason, despite the fact that improved energy efficiency would be advantageous, the final choice of the material was NOES grade M400-50A (i.e., 0.5 mm thick laminations of non-oriented steel). The first part used for the initial experimental tests had a length of 10.6 m (constructed from eight modules, each with a length of 1.3 m), as shown in Figure 1. The testing was carried out by the research partner [PERSON], who decided to begin the initial tests on a shorter part of the stator (Figure 1), with the later plans to extend the prototype to the full length (up to 60 m), so that the full expected longitudinal speed could be investigated, including acceleration and deceleration solely by electromagnetic means. The detailed electromagnetic design, efficiency estimation, power supply design and control, and performance testing were carried out as a separate part of the project (carried out independently by Zeleros), and therefore the details of their investigation are not included in this communication. The operating principle of the LLEA followed the switched-reluctance motor approach, with the 4:6 ratio of rotor/stator teeth. The stator was excited with a high-frequency converter configured for switching three-phase winding configuration (Figure 2a) and the mover provided the passive magnetic reluctance. No permanent magnets were used in this construction. The operating principle of this LLEA prototype is illustrated in Figure 2. One stator module (1.3 m long) comprises six \"teeth\" with the magnetising coils positioned on them. This configuration provides in effect a three-phase supply (phases 1-2-3), and facilitates control over the direction of movement (forward or reverse) along the main longitudinal axis. Each phase can be energised in a sequence so that the subsequent mover sub-parts can be magnetically attracted in the desired direction of movement (forward or reverse).