words & definitions
To: mail11:;-at-msd26.ENET.dec-dot-com (-at-teslatech)
Subject: words & definitions
From: "I am the NRA." <pierson-at-msd26.ENET.dec-dot-com>
Date: Mon, 27 Nov 95 16:32:54 EST
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>Just generally, I'm new to this air-core coil saturation concept.
I SUSPECT that two different uses/meanings of the word "saturation"
are being used.
In strict engineering discussion of magnetic circuits, with cores,
as used in power transformers "saturation" has a very specific meaning,
as below. (as i understand it...)
I believe most of the recent discussion here has used "Saturation" to
apply to the overall performance of an entire coil system, and its
ability to turn more watts in into more volts out. This a reasonable
use (IMO) of the term saturation, but not the one commonly used in
Classic Transformers convert essentially all the input current into a magnetic
current (flux) , that flows thru the core. It is possible to do without the
core, however efficiency suffers (or the transfomer must be big, or both).
Core materials, in "conducting" magnetic flux behave somewhat, but not exactly,
like wires conducting electric current.
One of the differences is that as the flux increases (more power passed thru
the transformer) the core gets "non linear". It ceases, fairly abruptly, to be
an efficient magnetic conductor. Losses go up. Output drops. There is no
analagous behavior, in the case of wire conducting electrical currrent. The
cure for saturation is simple: more iron (or whatever core is being used).
An AIR CORE coil, as a tesla coil, having no iron/steel/whatever core, cannot
saturate IN THIS SENSE. Air core coils/transformers are commonly used at
"high frequencies" where the losses in any core would be prohibitive. Losses
in the core go up with frequency. (ferrite cores, as adopted in RF work, are a
sort of middle ground...)