Re: UNITS

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Finn Hammer <f-h-at-c.dk> 

Ken,

0.80mm is the diametre of a wire the size of which lies inbetween a wire 
that is 0.79mm in diametre and one that is 0.81mm in diametre.

I`m sorry that there is no easy AWG equivalents here, but then, that`s the 
beauty of the metric system.

Because we can walk right into a motor rewind shop and get wire with 0.01mm 
difference.

Here is an explanation why it is easier to understand magnetics, if you 
take the SI approach:

Systems of Units:
      The internationally accepted SI system of units (Systeme 
International dÙnitès) is a rationalized system, in which permeability, µ = 
µo*µr (µo is the absolute permeability of free space or nonmagnetic 
material = 4pi*10^-7; µr is the relative permeability of a magnetic 
material). In the unrationalized CGS system, µo=1, therefore µo is omitted 
from CGS equations so that µ = µr. But the rationalization constant µo does 
not just disappear in the CGS system - instead, portions of this constant 
now show up in all the CGS equations, complicating them and making them 
more difficult to intuitively grasp. In the SI system, all of the "Garbage" 
is gathered into µo, thereby simplifying the SI equations.

This was taken from:
http://focus.ti-dot-com/lit/ml/slup123/slup123.pdf
and I owe it to Jan Wagner
http://www.hut.fi/~jwagner/tesla/
to have found the article in the first place.

Cheers, Finn Hammer


Tesla list wrote:
>Original poster: "Crow Leader" <tesla-at-lists.symmetric-dot-net>
>The AWG system makes sense, there is never confusion about "are you talking
>diameter or cross sectional area" as with metric. We do have MCM for large
>wires, but again, it's simple - MCM = 1000 circualr mils, that's it. What is
>say 0,8mm wire supposed to be?