The Building Factor (BF)—the ratio of actual assembled core loss to nominal Epstein test loss—can easily exceed 1.20 if mechanical stress is mismanaged. Preserving the virgin magnetic properties of Hi-B CRGO requires strict structural engineering during assembly.
- Compressive Stress Sensitivity: CRGO steel is acutely sensitive to compressive forces. A mere 2 MPa of localized compressive stress along the rolling direction forces 180° magnetic domains to reorient into 90° domains. This drastically increases hysteresis loss and spikes No-Load Loss (NLL) by up to 20%.
- Clamping Optimization: Traditional heavy steel clamping frames induce uneven mechanical stress and stray flux losses. Utilizing resin-bonded core technologies or fiberglass banding ensures uniform pressure distribution ($\le 0.5$ MPa), preventing localized domain degradation.
- Structural Rigidity: Lifting and tilting a fully assembled core can induce permanent plastic deformation if yoke-to-limb rigidity is insufficient. Precision Multi-Step-Lap (MSL) joints with calculated overlap lengths provide mechanical self-support, minimizing the need for extreme external clamping pressure.
As a supplier to the world’s #1 capacity transformer manufacturer, Chenfan Electric engineers custom magnetic cores that strictly control the Building Factor, ensuring theoretical efficiency matches real-world performance.