Unusual gap shape of ETD59 ferrite core?

[cupoftea]

Hi,
Do you know why this ETD59 core is gapped in such an unusual way?
Is it to reduce fringing flux heating the windings?

https://www.mouser.com/catalog/specsheets/EPCOS_ETD_59_31_22_DG.pdf

 

[mrinalmani]

Hi
This should definitely have to do with fringing losses in solid copper conductor. Two smaller gaps of length L each, will have lower heating effect on solid conductor than a single gap with length 2L.
Regards
Mrinal

 

[Taihung]

I saw this: https://www.digikey.com/en/product-highlight/e/epcos/distributed-gap-ferrite-cores
"

Distributed Gap Ferrite Cores​

EPCOS distributed air gaps enable a 70 percent reduction in additional copper losses​

TDK Corporation presents the EPCOS distributed gap ferrite cores are designed to permit higher operating frequencies and smaller inductive components to be used in power supply systems. These ferrites enable additional copper losses to be reduced by up to 70 percent. By reducing electromagnetic emissions, the additional copper losses at high frequencies are also reduced. Thanks to the identical distributed gaps in the center posts, the magnetic field emission to the environment is effectively prevented.
"