Re: Current Distribution Re: Aluminium aka Aluminum Wire (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 05 Oct 2007 21:08:28 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Current Distribution Re: Aluminium aka Aluminum Wire (fwd)

Hi All,

>Inductance is NOT dependent on voltage or current, it is a physical property like length or width and exists whether or not any voltage or current is present.
>
Inductance is rather an ambiguous term. The property of inductance exist 
without any change, but without change, it is only a property or an 
ability, and nothing more. There is no induction without change. There 
is only the calculated inductance based on the size and shape of the 
conductor.

All this can easily get taken out of context. Does inductance change for 
a length of a conductor. Yes it does. Winding a conductor into a coil 
will increase it's self inductance.

If we induce a current across an entire coil and mentally break up the 
coil into several segments, the total inductance will be the net sum of 
all segments. But, there is more than coil size and shape that plays a 
role for changing the inductance. If there is "something" that has the 
ability to alter the "property" of inductance, then the net inductance 
will change. When the field changes, the flux density changes. This 
change in flux density will alter the induced voltage. Each segment will 
have different values of induced voltage (the reactance of each section 
will be different one from the other), but the net inductance is still 
the total of all segments.

Now imagine high frequency where the usable current carrying geometry of 
the wire is changing and currents are disproportionate. Each segment 
will have a different inductance than the next because the "property" or 
"ability" to induce a voltage has been changed by the new geometry and 
the time varying magnetic field is varying the distribution of current 
within the conductor. The result is a decrease in the net inductance of 
all segments. The inductance has decreased.

That's my 2 cents.
Take care,
Bart