"John Larkin" wrote in message
...
On Wed, 18 Apr 2007 12:26:09 -0500, "amdx" wrote:

Hi,
Does the orientation of flux affect the saturation?

Please see attached picture at ABSE.
Subject: Variable Inductor Help
My thought is to build a variable inductor by installing a toroid in the
gap
of a potcore. The potcore would then have near normal ungapped inductance.
However when the toroid is saturated (by turns installed on the toroid) it
would be invisible and act like a gap. Hopefully this effect could be
modulated by the amount of current through the turns on the toroid.The
problem I have is the orientation of the flux, the potcore center flux is
vertical and the toroid is horizontal. Any thoughts?

Mike



It'd guess that it would be hard to get that tiny winding to saturate
the gapped toroid, and cooling would be nasty.

How about this:

Wind two separate pot cores #1 and #2, each with two windings A and B.

Connect windings A1 and A2 in series, and also connect B1 and B2 in
series but opposite phasing. Use the A circuit for your AC signal, and
run DC current through the B circuit. Current in B will saturate both
cores, but signal in A will not couple into the B circuit because of
the phase difference.

John

Hi John,
That may well work, but I wanted a different material as the saturating
piece. Hopeing to find a material easy to saturate.
Mike