On Friday, September 5, 2014 9:15:37 AM UTC-4, Daniel wrote:
> On Saturday, 1 January 2000 19:00:00 UTC+11, D.H. Kelly wrote:
>
> > Your concern over this assertion was well placed. It would have been
>
> > possible to use integral of H.dl around loop = current enclosed- hence H
and
>
> > flux outside the core whatever the mu. (which you did as part of your>
development.) You went a step further and I, for one, am glad that you did.
>
> > Don Kelly
>
> > dkelly@nabunalimo.lark.com
>
> > remove the bull to reply
>
> >
>
> > BillyFish wrote in message
>
> > news:20000101001804.15555.00000237@ng-ce1.aol.com...
>
>
>
> > > Let me point out that this whole thread started because someone made the
>
> > > assertion that increasing the mu of the core to very high values would
>
> > prevent
>
> > > any flux outside the core. I think that the consensus now is that such
an
>
> > > assertion is erroneous. This glib assertion suckered me in. In a sense,
>
> > it
>
> > > was a scam artist at work. Well meaning maybe, but a scam artist
>
> > nevertheless.
>
> > > I just had to *understand* why it was erroneous. The scam misses the
>
> > point
>
> > > that a parallel H and E do not generate a Poynting vector. Once that is
>
> > > realized, everything else follows rather easily.
>
> > >
>
> > > Bill
>
>
>
> so after 14 years was the conclusion reached that leakage inductance is in
fact essential to transformer power transfer.. or an unfortunate, usually
small but inescapable component which reduces coupling and hence reduces
efficiency?
>
>
>
> thx...
On Friday, September 5, 2014 9:15:37 AM UTC-4, Daniel wrote:
> On Saturday, 1 January 2000 19:00:00 UTC+11, D.H. Kelly wrote:
>
> > Your concern over this assertion was well placed. It would have been
>
> > possible to use integral of H.dl around loop = current enclosed- hence H
and
>
> > flux outside the core whatever the mu. (which you did as part of your>
development.) You went a step further and I, for one, am glad that you did.
>
> > Don Kelly
>
> > dkelly@nabunalimo.lark.com
>
> > remove the bull to reply
>
> >
>
> > BillyFish wrote in message
>
> > news:20000101001804.15555.00000237@ng-ce1.aol.com...
>
>
>
> > > Let me point out that this whole thread started because someone made the
>
> > > assertion that increasing the mu of the core to very high values would
>
> > prevent
>
> > > any flux outside the core. I think that the consensus now is that such
an
>
> > > assertion is erroneous. This glib assertion suckered me in. In a sense,
>
> > it
>
> > > was a scam artist at work. Well meaning maybe, but a scam artist
>
> > nevertheless.
>
> > > I just had to *understand* why it was erroneous. The scam misses the
>
> > point
>
> > > that a parallel H and E do not generate a Poynting vector. Once that is
>
> > > realized, everything else follows rather easily.
>
> > >
>
> > > Bill
>
>
>
> so after 14 years was the conclusion reached that leakage inductance is in
fact essential to transformer power transfer.. or an unfortunate, usually
small but inescapable component which reduces coupling and hence reduces
efficiency?
>
>
>
> thx...
Tomtech,
Thanks for all that replied with additional info.There is still confusion
when speaking of "flux Density" and "Field Intensity" when referring to
transformer fluxes. Yes, when not on load, there is some slight leakage flux,
for example in spaces between
the winding and the core. The H MMF still produces some, small amount of flux
in that space, even thought the core flux (flux density, not flux intensity)
is MUCH larger. When the secondary is under load,(resistive), the MMF produced
by the secondary is
almost exactly balanced by the additionl (load component) of MMF from the
primary. These two fluxes produce NO additional flux in the iron core as they
balance each other. The tow are not EXACTLY in phase with each other, and that
is the key to
understanding some of the aspects of power transfer in the Transformer. Under
load conditions, the Leakage flux is conducted in the iron up to the secondary
winding, depending on winding geometry, so is not all in the air, but the air
path does
contribute to the lions share of the reluctance. Remember, on load the
"Leakage" flux does not have the same "Flux Density" as the core, but many
times the "Flux Intensity" and MUCH more energy than the B flux in the core.
Take a look at textbook "
Magnetic Circuits and Transformers, A first course for Communications
Engineers, still in print from staff at MIT. It is well worth the effort to
digest it. Yeah, on my reference to signal transit times thru audio inter
stage transformer, I neglected
some other but important transfer mechanisms, namely capacitive coupling as
well as the bothersome inter winding resonances, etc. It is a rater involved
subject, that appears simple at first blush. For sure the alternating core
flux does indeed created
the induced EMF in the secondary, you can have a air core too, at 60 HZb but
the large magnetizing current would render the transformer so inefficient as
to be useless, as the low permeability of air would require many, many primary
turns......
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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