Re: rotating magnetic field



<phil-news-nospam@xxxxxxxx> wrote in message news:h0a6ue0158d@xxxxxxxxxxxxxxxxxxxx
On Wed, 3 Jun 2009 20:53:12 -0700 Don Kelly <dhky@xxxxxxx> wrote:

| Now you have pissed me off. I had actually dismissed and forgotten your
| contentions there. I dealt with them before- If you prefer to hand-wave,
| that is your prerogative- If I choose to ignore the hand-waving -that is
| mine. Since there is no evidence that rotating the magnet rotates the field,
| then it is up to you to obtain such evidence. Until then , you are simply
| blowing bubbles in the bathtub.

Strange, considering my calmness and lack of any emotion in this whole thread.
---
Not quite so but fair enough.
-------

The "evidence" is that if it does not, there is a contradiction in physics.
I explained it in a couple previous posts, and I posted it again just this
evening in this thread.
------------
And your explanation

"But in fact, a field is an extension of the magnet itself. Or more accurately
it is an extension of each atom or particle of that magnet, summed together
with a non-zero orientation."

doesn't deal with the field except for the "summation" which for a magnet producing a uniform field when stationary, will still produce the same field when rotating- the position of individual atoms is immaterial as the sum is all that we can detect.

d
>

| This was dealt with long ago as were some of your ideas about magnetic
| circuits/devices.

And which were those?
---------
Most of them.
---


|> Well, then you added on to it that you did not want to accept that volts
|> divided by amps gives ohms in all cases (even if those ohms are not series
|> resistance ohms in some cases).
| ----------
| I have no problem with V/I having the units of ohms. (in fact the ohm is
| defined as volt/ampere. Ohm found a linear relationship V=RI and defined
| the slope of the line as V/I or volts/ampere - later called the Ohm.

Then you should have no problem making a reference to system A that has a
higher V/I ratio (compared to system B with a lower V/I ratio) has being
one of a higher number of ohms ... a higher impedance.\
---------
No problem there - however there is no significance as far as power transfer is concerned
100V/1A =100 ohms and power 100 watts, 100000V/1ma =100M ohms and 100 watts
So what's the big deal? In both cases , the impedance involved is the "series" impedance seen by a Thevenin source.


| That doesn't mean that an ideal source E driving a current I through an
| external circuit is a resistor (and particularly not one that obeys Ohm's
| law). It is useless to think of it that way as it gives no useful
| information. I have iterated this before and that is the point that you have
| repeatedly missed.

I never said the source was a resistor. I characterized the system as one
of a higher impedance. That doesn't mean it is a resistor. Even if the
generator is entirely a superconductor, it will still be part of a system of
a specific impedance when it has a specific voltage / current ratio, which
in such a case (superconductor) is determined by the transmission line loss
and load impedance. If the transmission line is also a superconductor, then
it is just about the load impedance alone (in steady state DC where inductive
and capacitive effects do not apply).
--------
No problem there. The source voltage current ratio is the same as the total effective series impedance of the Thevenin source plus the line and load and typically is dominated by the load in power applications.
Again, no big deal.

Of course, if the load is a superconductor, it isn't much of a load. You
have to have some kind of voltage / current ratio there to transfer power,
be that a form of resistance, or something else.


| Now, given a complex network of sources and impedances, the Thevenin (the
| concept that you don't want to deal with as it is real world) model reduces
| to an ideal source behind a (constant) impedance AS SEEN FROM THE LOAD. It
| tells nothing about what is actually behind the connection point and the
| load doesn't give a damn. Again, that is the point thatr I made and you
| missed.

The Thevenin model is simply not something I referred to. You can use it in
whatever kind of analysis you want.
----
You think that you have not referred to it but in fact it is implicit in your statements.
-----------


| Nor do I believe in your (infinite) Transmission line concept - particularly
| as the behaviour of a generator connected to a load is not characteristic
| of a transmission line. By the way, when you get reflections at the
| terminals of a transmission line, it is still a transmission line. This and
| other comments indicate that you really don't get it.

If you don't believe in infinite transmission line concepts, then I guess you
don't know transmission lines. This is a concept that has been around for a
long time. I did not invent it. I first read about it around 1970 or so, and
finally understood it in the early 1980's.
--------
Is it that you have been exposed to the concept of the inductance per unit length and the capacitance per unit length based on the line being "ideally infinitely long " ? Then through the " telegrapher's equations" whose solution leads to the characteristic Zo of a line (any length) as well as other factors?
If so, then you still don't understand. If something else, tell me. I will listen.

I was first involved with this in 1954 and since then have dealt with it on and off since then- and have gone over premises involved more than once to prove it to myself.
If you have something regarding this that I don't know, then I am willing to listen. If what you say is not correct , then I will disagree strongly. Such disagreement will be based on both academic and practical experience - as has my previous disagreement been based on. It will not be "hand waving".
OK?

--
Don Kelly
dhky@xxxxxxxxxxxx
remove the x to reply

.

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