What is a formula for magnetic conductivity

[srinath]

I am looking for magnetic conductivity table or formula.
My question is this ...

If I took a lets say N50 magnet and stuck it to a steel plate 1/4" thick, what would the rating be on the other side of the plate.
Will it be more for say steel and less for cast iron, etc etc.
I know it will be more than 1/4 of air ? How much more ?

Cool.
Srinath.

 

[DF96]

'Magnetic conductivity'? You might get some help by googling 'magnetic flux calculations'. Bear in mind that calculation is only tractable for situations with simple geometry and useful symmetry - everywhere else you need to do a field-level simulation.

'Rating'? Do you mean field strength?

 

[srinath]

Let me try that ...
See I have a carver planar magnetic tweeter I took apart.
The thing has magnets that are 10mm X 10mm and about 150mm long. They are magnetised through the thickness, so the magnetic pole is 10mm X 150mm. It is no stronger than n8. Cos its alnico or ceramic. So N5 or N8.

My idea is to put a Neodymium magnetic base of 10mm X 3mm X 100 mm strips and then a 6mm steel bar on top. Neodymium is available from n25 all the way to n52.
I want about N8 @ the top of the steel strip.
What is the strength of neo I need as the base. That is where this question is based on. I'll check what I find.

Thanks.
Srinath.