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Re: B vs H/ Transformer analogies of Poynting Vector.

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Harvey,

All of the engineering books that I have has always used the terms of B being the magnetic flux density (webers/m^2 and sometimes called the tesla :o)) ) and H being the magnetic field intensity (amps/meter). These units are in the MKS system. CGS use strange (I guess I think MKS) units like maxwells, guass, oersteds, etc). B=uH. Phi(webers)=BA. Mu (u) has units of henery/meter and inductance (henery) is webers/amp. Fun to play with unit analysis. Hope I got all the pieces for you to prove this is a self consistant set.

Gerry R

Original poster: Harvey Norris <harvich@xxxxxxxxx>


Thought the eggheads would like this one. Sorry my
physics is fuzzy, and I shouldnt care but do...
However the debate goes on, these authors state;
"leakage flux is a essential aspect of the ideal

They have to rationalize how a transformer can work
without flux lines crossing the cores...

When I went to school B and H were strictly defined
when talking about effects. B is defined as a cross
section of amp/turns per area of cross section: H was
the magnetic intensity per unit length of core...
>From records...
Around the early 80's I also attended Akron State Univ
after dropping out, but the different text from that
same Elementary Classical Physics course does not seem
to deal with H at all, as the other text did. In the
early 90's I purchased another Physics text,(Physics
for Scientists and Engineers) in which the following
is noted on pg 654;

We have named B the magnetic field and H the magnetic
intensity. These names are not universal. Sometimes B
is called the magnetic flux density and H is called
the magnetic field. Admittedly, the terminology is
confusing, and universal adoption of a single set of
terminology is unlikely in the near future.
Fortunately, the usage of the symbols B and H as we
have defined them is nearly universal. Thus the
calculation of a magnetic force on a moving charge or
a current nearly always involves B; similarly H is the
appropriate field in Ampere's Law.

Of course the above authours deal with H, and never
mention B, so I see every explanation can be made
according to the authours viewpoint. according to how
they wish to explain effects...