CHH Power focuses on core structure improvement (a manufacturer-controllable factor for additional no-load loss) to reduce no-load loss effectively. By optimizing core seams, lap width, and width selection, we achieve uniform magnetic flux density distribution—lowering local magnetic density at core corners without changing the core’s effective cross-section. Below are the three practical, cost-effective optimization strategies, verified by test data.
1. Replace Staggered Seams with Third-Order Seams
Core Principle
Gaps at silicon steel sheet joints of the core increase magnetic resistance. This elevates local magnetic density of adjacent laminations, leading to higher no-load loss and excitation capacity.
Optimization Logic
- More seam stages reduce local loss in the seam area, but the marginal benefit diminishes with additional stages.
- Higher seam stages also increase processing difficulty, silicon steel sheet cutting time, and core stacking complexity—raising production costs.
- Third-order seams balance performance and process feasibility: alternating stacking of three lamination types, adding only one sheet type to the core column, slightly increasing process complexity while significantly improving magnetic properties.
Test Verification (S9 Series Transformers)
CHH Power tested S9-800/10 and S9-1000/10 transformers with the same design, structure, and materials, only varying core lap joints:
- Staggered seams: 2 units (1000kVA).
- Third-order seams: 3 units (1000kVA) + S9-800/10 units.
Result: Under the same core column cross-section, third-order seams reduce no-load loss by 7%–8% on average compared to staggered seams—with only slight increases in silicon steel cutting and core stacking time.
2. Reduce Core Lap Width to Lower Local Magnetic Density
Core Principle
The lap width of the joint area between core legs and transverse yokes (at core lamination corners) affects no-load performance. Larger lap areas expand magnetic flux paths, increasing no-load loss.
Key Data Support
Tests show that for 45° joints, every 1% increase in lap area raises no-load loss by 0.3%.
CHH’s Optimization Measures
- Balance no-load loss and mechanical strength to select the optimal lap area.
- Modify the core’s tower-shaped stacking joint area: reduce the size of some triangular holes in the core to lower local magnetic density at these holes.
- Adjust core lamination angle: reduce from 10mm to 5mm. This increases the cross-sectional area of triangular cavities at core corners, inevitably reducing local magnetic density—achieving significant energy savings.
3. Reasonably Select Core Width to Reduce Corner Weight
Core Principle
Transformer core no-load loss is related to both unit iron loss and core weight. Core corner weight is a key part of total core weight, directly impacting both transformer cost and no-load loss.
Optimization Strategy
CHH Power optimizes core width design to reduce unnecessary corner weight:
- Avoid excessive core width that increases corner material usage.
- Match core width to magnetic flux requirements, ensuring uniform flux density while minimizing core material consumption.
Dual Benefit: Reduces core material costs and lowers no-load loss (since less core weight means less hysteresis and eddy current loss).
Critical Design & Production Notes
- All optimizations aim for uniform magnetic flux density: the core’s effective cross-section remains unchanged, avoiding negative impacts on transformer load capacity.
- Third-order seams require precise lamination stacking control to ensure joint alignment—CHH Power uses automated stacking equipment to maintain process stability.
- Lap width reduction must not compromise mechanical strength: we conduct structural stress tests to confirm core stability after optimization.