Current sense transformers on ETD type bobbins?

[Easy peasy]

Actually a CM choke with the windings on each side is one of the few examples of where the core permeability makes a difference, with no core the mag field is free to go thru the air in all ways and there will be less linkage to the other coil, with a high-u core the mag field lines will be more predominantly in the core and there will be less (lower density) non linked leakage flux. Taking the core out in this instance will lead to measurably higher Llk...

 

[FvM]

Taking the core out in this instance will lead to measurably higher Llk...

Did you actually try?

I hypothesize it can be shown that this inequality is always satisfied

Lσ,aircore <= Lσ,cored

 

[treez]

I think on a torroid that may apply, but less so in a mating cores type, specially with a gap, and as weve heard in other posts, mating cores always have gaps, unless they are lapped to heck and back

 

[andre_luis]

Still in the field of assumptions, I believe that the core type POT, even having an unwanted small gap between the halves could feature a low leakage inductance due to the winding be confined inside a region magnetically self shielded, it's not ?.

 

[FvM]

I think on a torroid that may apply, but less so in a mating cores type, specially with a gap, and as weve heard in other posts, mating cores always have gaps, unless they are lapped to heck and back

It's not completely clear which statement your are commenting in your post, I guess it's about post #61

Taking the core out in this instance will lead to measurably higher Llk...