# Coil Design, Effictive Area (Ae) Quesiton

Discussion in 'The Projects Forum' started by electronice123, Sep 25, 2013.

1. ### electronice123 Thread Starter Senior Member

Oct 10, 2008
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Hello everyone,

I am working on my first transformer design using a powdered iron core.
I have designed transformers using ferrite before, but powdered iron is new to me.

The manufacturer does not provide the Ae (Effective area) of the cores they make.

They only provide the core dimensions and the "Magnetic Dimensions" L,A,V and W.

How can I find the Ae of these cores so I can do the math to ensure I don't saturate the core???

http://www.micrometals.com/parts_index.html

Or is the design process different when using iron powder?

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
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Knowing the inductance factors is not the entire point. Rather, you also need to know the saturation flux density of the material.

Last edited: Sep 25, 2013
3. ### electronice123 Thread Starter Senior Member

Oct 10, 2008
302
0
Saturation Flux Density of the material is 1.1T

I just need to calculate the volt-seconds to be sure I don't saturate the core.

4. ### t_n_k AAC Fanatic!

Mar 6, 2009
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I notice from the web site the B-H curves for the various material grades are available. One could use these to predict the likely performance based on the particular application. It looks like the materials have a relatively smooth transition to the saturation region.

5. ### t_n_k AAC Fanatic!

Mar 6, 2009
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Presumably one would use the given magnetic area as the equivalent of your desired Ae.

6. ### electronice123 Thread Starter Senior Member

Oct 10, 2008
302
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That's where I am confused.

I have only designed coils with ferrite cores where the Ae was given.

What do the magnetic dimensions l,A,V,W represent?

7. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
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I would say l - effective magnetic path length, A - magnetic path cross sectional area, V - effective core volume, W - winding window cross sectional area.

The inductance factor (also given for the various cores) should equate to

${\frac{\mu_o \mu_r A}{l}}$

The data sheets (curiously) quote a "μo" value which I would presume is actually the relative permeability, rather than the free space permeability normally assigned to μo.You could possibly cross-check the equivalence for yourself by plugging in the manufacturer's values given in the data.

8. ### DickCappels Moderator

Aug 21, 2008
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Listen to t_n_k.