Effective cross-sectional area

[Sudalai]

Hello sirs,
How to calculate the cross-section area too toroid core? kindly explain this

 

[Tom.G]

(OutsideRadius - InsideRadius) x Height = Cross Sectional Area
(0.155 - 0.078) x 0.125 = (0.077) x .125 = 0.009625 Cross Sectioanl Area

 

[berkeman]

Welcome to the PF.

Hello sirs,
How to calculate the cross-section area too toroid core? kindly explain this

You can also look at the manufacturer's datasheet for the core you are using. The core cross-section may not be exactly square, depending on the core. The area will usually be listed in the datasheet to be used as part of the calculation of the magnetic properties of the core...

https://product.tdk.com/info/en/products/ferrite/index.html

 

[Sudalai]

View attachment 241233
(OutsideRadius - InsideRadius) x Height = Cross Sectional Area
(0.155 - 0.078) x 0.125 = (0.077) x .125 = 0.009625 Cross Sectioanl Area

Dear Mr, tom
I saw a lot of websites I got these formula
OD-ID/2*H OR OD-ID/2*H*S.F, which one is correct

 

[Sudalai]

Welcome to the PF.

You can also look at the manufacturer's datasheet for the core you are using. The core cross-section may not be exactly square, depending on the core. The area will usually be listed in the datasheet to be used as part of the calculation of the magnetic properties of the core...

https://product.tdk.com/info/en/products/ferrite/index.html
View attachment 241269

Thanks for your reply this will be helpful to me

 

[Tom.G]

Dear Mr, tom
I saw a lot of websites I got these formula
OD-ID/2*H OR OD-ID/2*H*S.F, which one is correct

I don't know what "S.F." is so I can not answer that.

I can guess that "S.F." is Shape Factor to account for shapes that are not rectangles. If the cross section is round or oval and not a rectangle, then a Shape Factor correction would be needed to find the area.

Many catalogs ignore rounded corners because that make very little difference in the calculations. The variations in the core material itself is larger than slightly rounded corners.

Also, some parentheses are needed in the above to get the math correct.
(OD-ID)/2*H

Cheers,
Tom

 

[Sudalai]

Dear Tom,
S.F means stacking factor refer to below link

 

[Tom.G]

Ahh, OK... S.F. is used to account for the percentage of the overall core that is NOT magnetic material, but is insulation, glue, potting compound, etc.

I have not used strip-wound cores so I was not familiar with the term. The ferrite cores that I am used to have an effective S.F. of 1 and it is left out of the formula. Addressing your question directly, of the formulas you asked about, the one that includes S.F. is more complete.

S.F. is left out when it is close enough to 1 to ignore, or when the manufacturer has already taken it into account when quoting the permeability.

Hope this helps.

Cheers,
Tom