The iron core is subject to strict technical standards regarding material properties, serving as the foundation for the transformer's low-loss and highly stable operation. It must be constructed from grain-oriented silicon steel sheets characterized by high magnetic permeability and low loss; the material ensures uniform and stable permeability while keeping hysteresis and eddy current losses within industry-specified limits, thereby effectively reducing no-load losses and no-load current. The material itself is dense, free of impurities and delamination cracks, and exhibits excellent resistance to high temperatures and magnetic saturation; it maintains integrity without issues such as magnetic flux disruption or saturation failure under rated loads or slight overloads. Furthermore, the insulating coating on the silicon steel sheets must be uniform, intact, and strongly adherent-resistant to oil and high temperatures-to prevent inter-laminar short circuits that could cause localized overheating or increased losses.
The stacking and structural assembly of the iron core are governed by rigorous technical requirements to ensure a neat overall structure and an unobstructed magnetic path. The laminations must be flat, smooth, and uniform in thickness, with precise cutting dimensions; the stacking process requires strict staggered assembly with minimal, uniform gaps to prevent increased magnetic leakage and noise caused by excessive air gaps. The assembly is tightly compressed and highly aligned, free from defects such as curled edges, looseness, or misalignment; the core limbs and yokes fit tightly with symmetrical structuring, ensuring a uniform and rational magnetic path distribution. Once assembled, the core is structurally rigid and stable, capable of withstanding electromagnetic vibrations and external environmental forces during long-term operation without loosening, deformation, displacement, or oscillation, thereby structurally guaranteeing operational stability and noise compliance.
The iron core's operating parameters and insulation protection must comply with safety technical specifications for power equipment and be suitable for long-term, continuous operation. The core must be reliably grounded using a standardized, single-point grounding method to eliminate issues like multi-point grounding or poor connections, thereby preventing floating potentials that could trigger partial discharge or overheating faults. Surfaces and edges must undergo passivation and grinding to remove sharp burrs, preventing insulation breakdown caused by electric field concentration at sharp points. Furthermore, the insulation clearances between the core and components such as windings and clamps strictly meet specifications, ensuring excellent insulation performance and the ability to withstand both normal operating voltages and transient overvoltages. Prior to leaving the factory, the equipment undergoes rigorous verification-including loss measurements, noise testing, and insulation tests-confirming that all parameters comply with standards and ensuring stable, safe, and long-term operation of the core under various complex operating conditions.
