The initial stage of transformer core manufacturing involves raw material selection and precision cutting, serving as the foundation for ensuring low core loss and dimensional accuracy. Production begins with selecting the appropriate grade of grain-oriented silicon steel sheets or amorphous alloy strips based on the transformer's capacity and energy efficiency rating. Upon arrival, raw materials undergo visual inspection to reject sheets exhibiting oxidation, warping, or coating damage. Subsequently, specialized CNC equipment is used to cut, blank, and notch the material according to design specifications, ensuring uniform thickness and smooth, burr-free edges for every silicon steel sheet. After cutting, the sheets are sorted and organized to prevent dimensional deviations and material mixing, thereby laying a solid foundation for the subsequent stacking and forming processes.
Stacking and assembly constitute the core phase of core formation, directly determining the overall precision and operational stability of the core. Conventional stacked cores utilize an interleaved stacking technique, where cut silicon steel sheets are layered with staggered joints; this ensures that the gaps at the joints between core limbs and yokes are uniform and minimal, effectively reducing magnetic flux leakage and operational noise. Throughout the stacking process, flatness and alignment are continuously monitored to prevent issues such as misalignment, edge curling, or excessive gaps. Once the specified thickness is reached, specialized fixtures apply uniform pressure to ensure consistent overall compactness. In contrast, wound cores employ a continuous winding process, shaping the silicon steel strip into a closed-loop structure according to the design curvature; this eliminates the need for segmented joints, resulting in a more continuous magnetic circuit and lower losses. Post-forming, the core undergoes a curing and setting process to ensure structural stability and resistance to deformation.
Following formation, the core undergoes finishing procedures, including grinding, insulation inspection, structural reinforcement, and final factory testing. First, the edges, corners, and joints of the core are precision-ground to remove sharp burrs, thereby preventing corona discharge that could damage the insulation structure. Next, the surface insulation coating of each silicon steel sheet is inspected to confirm the absence of damage or inter-laminate short circuits, ensuring that inter-laminate insulation performance meets required standards. The assembled core is then reinforced and secured using clamping components, binding straps, and insulating spacers; specialized grounding strips are installed to ensure a single-point grounding connection. Finally, the unit undergoes comprehensive dimensional verification, as well as loss, noise, and withstand-voltage testing. Only after all parameters meet the required standards is the core approved for storage and assembly, ensuring it satisfies the operational requirements for the transformer's long-term, safe, and stable performance.
