Losses due to fringing flux
Several methods exist to avoid this extra loss, either by playing with the gap or with the winding. The latest will be discussed in this document.
Two tests were done for the design
While fringing flux loss is unavoidable from the moment there is a gap, it can be reduced by placing every wire in the winding beyond 3 times the gap length, which can be done easily with custom-made coil formers. Other methods, like distributed gaps or the use of lower relative permeability materials, will be discussed in future documents.