## 4 Conventional Method for Studying Losses in Electrical Steels  
The manufacturing processes of electrical steels play a crucial role in determining these steels' total losses. Plastic deformation increases hysteresis loss while reducing excess losses, whereas annealing promotes grain size growth, resulting in a decrease in the former and an increase in the latter (as depicted in Figure 5). In the case of non-oriented electrical steels, the total losses, at 1.5 T and 60 Hz, vary from 10 W/kg to 3 W/kg in the annealed condition, as indicated in steel manufacturers' catalogs [29]. Motors, generators, and transformers are vital components in power systems, and their efficient design is essential to ensure regular power delivery while minimizing power loss. Recent research in this area has primarily centered around optimizing power loss. The consideration of power loss is a crucial aspect of machine design, and the core material's magnetic properties at special frequencies play a significant role. Consequently, there is fierce competition between material designers to develop the most efficient materials with minimal power loss [30]. In these machines, power loss is commonly distributed into three components: copper loss (\(P_{cu}\)), which occurs in the machine windings; mechanical loss (\(P_{me}\)) caused by rotating parts or friction, including bearing abrasion; and magnetic core loss resulting from alternating magnetic fields. Magnetic core loss arises from three primary sources: eddy current power loss (\(P_{e}\)), hysteresis loss (\(P_{h}\)), and anomalous loss (\(P_{a}\)) [31]. The magnetic cores of electrical machines and magnetic devices have a vital function in concentrating magnetic fields, wherein they achieve this by maximizing the inclusion of magnetic flux as possible due to the dynamic nature of the flux [32]. However, this concentration of flux induces an electromotive force in the core lamination, resulting in the generation of eddy currents and subsequent energy loss in the form of an increase in heat along the paths of these eddy currents [33]. Among the different loss components, eddy current power loss (\(P_{e}\)) has been observed to be the most significant and, in certain cases, can even lead to complete machine failure [34]. To address this issue, cores are constructed using thin stacks of laminations, typically ranging from 0.23 to 0.65 mm in thickness, depending on the material type and application. Figure 4: An illustration of the changes in loss, permeability, and magnetostriction of a typical Grain-Oriented (GO) steel Epstein strip when magnetized along its longitudinal direction (RD) at 1.5 T and 50 Hz while simultaneously applying external stress along the same direction [27]. By laminating the material, the flow of eddy currents is forced along long and narrow paths, significantly reducing their magnitudes and the associated heat inside the material [35]. Moreover, both sides of the laminations are coated with insulating sheets to avoid direct contact between the layers, which further reduces eddy current circulation in the core [36]. This insulating coating also contributes to reducing hysteresis and anomalous loss by beneficially applying tensile strength to the material [37]. The application of tensile stress to a material aids in the minimization of losses by decreasing the size of domains perpendicular to the direction of magnetization and narrowing down the domain wall's layout, leading to a decrease in anomalous loss by reducing the average domain wall velocity. Additionally, the addition a high silicon content of 3% to a material increases its resistivity, further reducing eddy currents [32] and thus enhancing the efficiency of new electrical devices. Breaking down losses into hysteresis and eddy current factors provides valuable insights into the features influencing those losses and serves as a predictive tool for losses in electrical machine cores.