Stacking factor 96% or above, burr height 0.02 mm max
No-load loss 8–15% below GB/T 6451
In detail
How we build it, and where it fits
The laminated core is still the workhorse of power transformer design. At ZWILLIS every core is built on a CNC cut-to-length line that shears grain-oriented silicon steel to exact lengths and angles, then stacks it in a full-mitre step-lap pattern. The step-lap joint spreads the air gap over several staggered steps, so the magnetic path stays continuous and the exciting current stays low. That is where the 8–15% no-load-loss margin against GB/T 6451 comes from — not from luck, but from joint geometry and burr control kept under 0.02 mm.
Typical applications cover oil-immersed power transformers from 30 kVA up to 240 MVA and dry-type units up to 35 kV. Cores can be delivered stacked and banded, or as a complete kit with clamps, tie plates and insulation ready for coil assembly. Every batch is dimension-checked and loss-sampled before packing.