Choice of Core

[scopeprobe]

Hi,
I'm seeking some clarification on the use of the I Squared L Graphs on Page 38 of the ferroxcube databook https://www.ferroxcube.com/en-global/download/download/11

I have a requirement for an inductance of 650uH with a peak current of 1A which if i use the I squared L equation equates to a I2L value of 0.00065 which is a value below all cores.

I've done some other maths which suggest i should use RM8 but it would be nice if i could understand how to cross reference here.

What am i missing?

 

[mtwieg]

The RM8 contour intersects y=0.00065 at around x=0.15, so this is telling you to use (at least) an air gap of 0.15mm

 

[scopeprobe]

The RM8 contour intersects y=0.00065 at around x=0.15, so this is telling you to use (at least) an air gap of 0.15mm

mmmm. Can you see what am i doing wrong here?

The RM8 Line looks to intersect the Y axis at 0.0045 (almost half way between 10e-3 and 10e-4 which is 0.01 and 0.001 Respectively). I'm obviously missing something as 0.00065 is a order of magnitude below all the cores which is surely wrong