Hi, I can't find my inductance calculations book. Say that you were considering magnetic flux linkage more from a geometric perspective: -Does the mutual coupling coefficient for a series of coils all on the same steel core add up to a maximum total of ~1? Because I tried simulating a three phase 'E' core TX on LTSpice, and I had issues making the coefficients between coils near 1 (it tells me I've made an impossible relation or something). -For example, if you were looking at a three phase Isolation transformer, ignoring self-couplings, what would the coupling coefficient between one primary coil to another primary coil be, approximately? Intuitively, I thought it'd be about M = 1/2 between each adjacent primary pair of coils, and the same mutual coupling coefficient between adjacent primary-secondary pairs, with each of the primary-secondary pair which are sitting on the same limb at about M: ~1. However, given the LTSpice, maybe it's more like M = 1/3 between adjacent limb coils? Similarly, I'm wondering how much of a difference (improvement) would a bifilar winding make to [reducing] the amount of leakage flux, and how much is going to couple through the core to another coil anyway (because the steel permeability is so high). Thank you!