Thanks,
On similar lines, we now wish to wind a transformer for a Flyback on a ETD54/28/19 core with 1mm gap (N87 material).
We have a split output rail of +/-40V, 4A. We will thus have two secondary windings, and these will be interleaved between the primary which will be split into three equal layers.
So we have a primary of 30 turns total, and a split secondary of 22 turns total. Each winding is made of three paralleled strands of SWG21 enamelled copper wire.
So we have this interleaved winding structure ,working from the core outwards.....
10 primary turns
11 secondary turns
10 primary turns
11 secondary turns
10 primary turns
We must have UK mains isolation between primary and secondary. (so 3mm margins)
The flyback is 330W peak, but average power is just 40W. (Guitar amplifier power supply)
Do you think we will be able to get a coupling factor of at least 0.994 with this interleaved winding strategy?
We fear that the 1mm gap size is just too wide to get this low leakage inductance?
The windings are each about 2.7mm wide (3 paralleled SWG21 strands) and this is wider than the core gap size so therefore we believe that this will help to reduce leakage inductance?
Epcos ETD54/28/19 core datasheet..(N87 material with 1mm gap)
https://www.italtras.com/filePDF/etd_54_28_19.pdf