Stupid question of the day....

[TokaMundo]

On Wed, 03 Aug 2005 06:13:41 -0500, John Fields
<jfields@austininstruments.com> Gave us:

On Wed, 03 Aug 2005 00:59:51 GMT, TokaMundo
TokaMundo@weedizgood.org> wrote:


Since a thin round copper wire has a very low emissivity it wont
give up its heat all that fast.

---
Ever hear of convection, dumbass?

Yes, and it has a surface area function, retard boy.

Got some numbers?

Your IQ is ten.

Or is this going to be another one of your
unsubstantiated claims?

Just as I stated, when the wire turns cherry red from current, it is
uniformly heated.

This will mean that your thermal
gradient won't be as prevalent as you suggest. The proof is when one
takes a copper wire and places it across a battery's terminals.
Notice how the entire wire turns a nice cherry red quite evenly, all
the way up to where it is attached to any form of sinking element.

---
I see. Just by _looking_ at the glowing wire you can tell what the
temperature differential is between the center of the wire and its
surface? Amazing!!!
---

The current throughout the wire will be even,

---
No, it won't. it'll be lower in the parts of the wire which are
hotter.

The entire wire has the same temp and the same heat. The only
exception is the connection points to the current source.

and it is that current
which generates the heat, or more precisely, the resistance to said
current flow.

---
The current changes the temperature of the wire, but it doesn't
generate the resistance of the wire.

I never said it did. I said the current generates the heat, and
then corrected to say that the resistance to said flow is the
condition which causes the generated. I didn't say a damned thing
about the current generating the resistance. That is a function of
the media the current is passing through.

Your remark is retarded.

The wire's resistance

No shit. That's what "resistance to said flow" refers to, dipshit.

and its
temperature coefficient of resistance are due to the resistivity and
tempco of the material the wire is made of.

No shit.

If the wire were giving up its heat real fast, like that of a finned
heat sink with air passing over it, I might agree.

---
Whether you agree or not is immaterial.

What you have to say about it is certainly immaterial.

The phenomenon occurs with
or without your permission.

The phenomenon of the entire wire being at the same temperature.

In the case of
bare copper, however, the temperature throughout the wire is going to
be very even. Your gradient will be nearly undetectable.

---
Point is, dimwit, it'll still be there.

You have no point. You and your stupidity has been exiled to the
pointless forest.

For a very large diameter copper bus, it MIGHT have a slight
gradient between the center and the outer surface, but not much. For
wire, it is as even as even gets.

Got some numbers, or is that just some more of your bullshit
opinion?

Got something that proves otherwise? Otherwise your rebuttal is
nothing more than bullshit opinion.

 

[TokaMundo]

On Wed, 03 Aug 2005 09:55:43 -0500, Bud <remove.BudNews@isp.com> Gave
us:

"Corona discharge" is *NOT* caused by AC or skin effect. Corona discharge
is caused by a high voltage gradient in the space around a conductor.
This
is a combination of the voltage applied to the conductor and the effective
radius of the conductor. A high voltage, or very small effective radius
can
increase the gradient to the point where the air is ionized. Simple proof
is that corona discharge is a problem with high DC voltage systems as well
as AC.

Sometimes hollow tubes are used for high frequency power conductors. This
reduces the weight and cost by eliminating the central part of the
conductor, where 'skin effect' has rendered the impedence high anyway. So
little admittance is lost for a great savings in material/weight.

VERY high frequency. NOT AC line frequencies.


Not so. I could show you several switchyards within a short drive that use
many hollow tube conductors all over the yard.

daestrom



I thought large diameter conductors in switchyards were for corona
reduction.

Large diameter turns (changes in direction) are. It is very bad to
make a sharp turn on a wire carrying HV as the field gradient at the
turn is high. Large radius turns are used to keep such gradients low.

Larger wire diameters also keep it lower. Look at an ionizer wire
in larger air purification systems. They use a very thin gauge wire
specifically because it will have a have gradient, and closely
resemble a point along its entire length.

---------
Not directly related, an engineering handbook lists the skin effect for
a 500MCM conductor as increasing the resistance by 2% - which I would
say is significant.

I would say that the material the wire is made of would make a
difference, and change that figure accordingly so such an arbitrary
number is pretty fucking vague.

Since TokaMundo is infallable,

Your an insulting bastard. Feel better now?

consider the possibiltiy that he is
actually the pope.

You're also a retarded bastard as well.

He has also been identified as a troll.

By John, the troll, and his minions. Are you one of them, asswipe?

 

[TokaMundo]

On Wed, 3 Aug 2005 18:29:47 +0200, "Alexander"
<electricdummy@hotmail.com> Gave us:

"TokaMundo" <TokaMundo@weedizgood.org> schreef in bericht
news:u670f1df7gqv6i8fdooj5i3c4o0hpdvg0o@4ax.com...
On Tue, 2 Aug 2005 22:58:33 +0000 (UTC), don@manx.misty.com (Don
Klipstein) Gave us:



Going by "High Frequency Resistance", pages 3323-3325 of the 43rd
edition of the "CRC Handbook":

They give a formula X=pi*d*SQR((2*u*f)/rho)*SQR(1000)

u is magnetic permeability, unity for copper.

rho is resistivity in microohm-cm.

They simplify this for copper, to x=10*d*.01071SQR(f)

d is diameter in centimeters, and f is frequency in Hz.

So, for 17 mm diameter copper wire at 60 Hz this "x" is 1.41.

Next is a table that gives ratio of AC resistance to DC resistance as a
function of this "x".

This table has an entry for 1.4, giving AC resistance 1.020 times DC
resistance.


The table I saw shows the AC and DC resistance as being exactly the
same for both.

Your flaw is where you failed to note the topic given in the CRC
handbook.

60 Hz is NOT high frequency... at all.

Try some calculations at 100 kHz and you'll see that those
frequencies down near zero (ie 60Hz) yield very nearly nil difference.

What is a high frequency?
If this is not defined in the source, then most of the time a high frequency
will be any frequency on what the voltage on the line cannot be taken equal
at every place of the line because of linelength and wavelength.

The voltage on the line is different along its length for plenty of
reasons, the least of which is skin effect.

By this 60Hz can be a very high frequency if you have a cable of several
kilometers.

A mile run at DC, and one at 60Hz won't yield significantly
different losses. If the voltage is high enough the drop will be even
less significant.

 

[TokaMundo]

On Wed, 3 Aug 2005 18:31:32 +0200, "Alexander"
<electricdummy@hotmail.com> Gave us:

"TokaMundo" <TokaMundo@weedizgood.org> schreef in bericht
news:ri70f1hhphqbr56v86alsaafq1feldqi8r@4ax.com...
On Wed, 03 Aug 2005 01:24:11 GMT, Repeating Rifle
salmonegg@sbcglobal.net> Gave us:

Some people say that there is no such thing as a stupid question.
Obviously
there seems to be no shortage of stupid answers.

Bill

Yours certainly contributed absofuckinglutely nothing, and would
certainly fall into the "stupid answer" category.

You remind me of a Firesign Theatre quote:

"Who wona second world war.. you so smart?"

Perhaps, if you are so informed, you should try giving an answer
that actually has facts in it that are in sync with the topic of the
thread, not merely its title.

Someone once tolf me something, I believe it wass: "Don't feed the trolls",
it seems to me that they are having a ball with food in abundance.

Just don't ever try to exclude yourself from the fray, because you

are just as deep in the shit as the next guy.

 

[John Fields]

On Wed, 03 Aug 2005 17:49:42 GMT, TokaMundo
<TokaMundo@weedizgood.org> wrote:

On Wed, 03 Aug 2005 05:31:54 -0500, John Fields
jfields@austininstruments.com> Gave us:

On Wed, 03 Aug 2005 07:19:12 GMT, TokaMundo
TokaMundo@weedizgood.org> wrote:


Sometimes I find it hard to believe that we actually call ourselves
sentient beings with the way some of you act.

---
I don't think anyone has ever called you sentient, much to their
credit.

Your a fucking kingpin when it comes to being retarded.
^^^^

Tsk, tsk, tsk...

Geez, Tokey, I'm not the one making all the spelling, punctuation,
and grammar misteaks. Oh, that one was just for fun.

--
John Fields
Professional Circuit Designer

 

[John Fields]

On Wed, 03 Aug 2005 18:30:47 GMT, "Bob Myers"
<nospamplease@address.invalid> wrote:

"TokaMundo" <TokaMundo@weedizgood.org> wrote in message
news:eg70f1hn1cl09doulbks19f3pjqgdaecs3@4ax.com...
On Tue, 02 Aug 2005 23:05:04 GMT, "Bob Myers"
nospamplease@address.invalid> Gave us:


My, again with the personal attacks; I suppose in the absence of
practical knowledge, that's about all one is left with.

As if declaring that someone has "no practical knowledge" isn't a
personal attack.

Fuck off retard. You have social problems.

Gee, someone must've received a bad grade last year in
their freshman circuit analysis class...

---
LOL, as much circuit design and analysis as he's done around here
makes me think they kicked his sorry ass out of the class!

--
John Fields
Professional Circuit Designer

 

[John Fields]

On Wed, 03 Aug 2005 18:48:51 GMT, TokaMundo
<TokaMundo@weedizgood.org> wrote:

Just as I stated, when the wire turns cherry red from current, it is
uniformly heated.

---
Sorry, Charlie, there'll still be a temperature gradient across the
diameter of the wire. There has to be, since the surface of the
wire will be radiating heat and being cooled by convection.
---

This will mean that your thermal
gradient won't be as prevalent as you suggest. The proof is when one
takes a copper wire and places it across a battery's terminals.
Notice how the entire wire turns a nice cherry red quite evenly, all
the way up to where it is attached to any form of sinking element.

---
I see. Just by _looking_ at the glowing wire you can tell what the
temperature differential is between the center of the wire and its
surface? Amazing!!!
---

The current throughout the wire will be even,

---
No, it won't. it'll be lower in the parts of the wire which are
hotter.

The entire wire has the same temp and the same heat. The only
exception is the connection points to the current source.

---
Nope. I'm sorry that you can't understand why the gradient _has_ to
be there, but it does, trust me. Or not, but continue on your
present course and all you'll do is further convince everyone that
you're as pig-headed now as you ever were.
---

and it is that current
which generates the heat, or more precisely, the resistance to said
current flow.

---
The current changes the temperature of the wire, but it doesn't
generate the resistance of the wire.

I never said it did.

---
Sure you did. If you go back and read the sentence more carefully,
what you said was:

"and it is that current which generates the heat, or more precisely,
the resistance to said current flow."

Now, if we restructure the sentence in accordance with your
instructions about preciseness, it reads:

"and it is that current which generates the resistance to said
current flow."

which is incorrect.

If the wire were giving up its heat real fast, like that of a finned
heat sink with air passing over it, I might agree.

---
Whether you agree or not is immaterial.

What you have to say about it is certainly immaterial.

The phenomenon occurs with
or without your permission.

The phenomenon of the entire wire being at the same temperature.

---
The only way there would be no resistance variation across the
diameter of the wire would be if there was no charge flowing through
the wire and it was in an isothermal environment. Period. End of
discussion.
---

In the case of
bare copper, however, the temperature throughout the wire is going to
be very even. Your gradient will be nearly undetectable.

---
Point is, dimwit, it'll still be there.

You have no point. You and your stupidity has been exiled to the
pointless forest.

---
You always regress to your fourth grade insults when you don't have
a leg to stand on and all you want to do is make noise, huh?
---

For a very large diameter copper bus, it MIGHT have a slight
gradient between the center and the outer surface, but not much. For
wire, it is as even as even gets.

Got some numbers, or is that just some more of your bullshit
opinion?

Got something that proves otherwise?

---
Sure, but you wouldn't understand it. Even if you did, you'd still
continue with your harangue in order to keep from having to admit
ignorance like you always do.
---

Otherwise your rebuttal is nothing more than bullshit opinion.

---
You've got the cart before the horse.

I hypothesized that there was a temperature gradient in a current
carrying conductor, originally, in a reply to one of John Larkin's
posts about skin depth.

That concept was elaborated on by daestrom, and then rebutted by
you, so unless you can prove that you're right and I'm wrong, my
hypothesis stands and the rebuttal, which _you_ made, is nothing
more than bullshit opinion.

--
John Fields
Professional Circuit Designer

 

[John Fields]

On Wed, 03 Aug 2005 18:56:32 GMT, TokaMundo
<TokaMundo@weedizgood.org> wrote:

On Wed, 03 Aug 2005 09:55:43 -0500, Bud <remove.BudNews@isp.com> Gave
us:

Not directly related, an engineering handbook lists the skin effect for
a 500MCM conductor as increasing the resistance by 2% - which I would
say is significant.

I would say that the material the wire is made of would make a
difference, and change that figure accordingly so such an arbitrary
number is pretty fucking vague.

---
Since very little of what you say is true, a reference would be
preferable to an opinion.

Something like this:

http://en.wikipedia.org/wiki/Skin_effect
could even help you to _prove_ your point.

--
John Fields
Professional Circuit Designer

 

[Michael A. Terrell]

John Fields wrote:

On Wed, 03 Aug 2005 07:19:12 GMT, TokaMundo
TokaMundo@weedizgood.org> wrote:

Sometimes I find it hard to believe that we actually call ourselves
sentient beings with the way some of you act.

---
I don't think anyone has ever called you sentient, much to their
credit.

--
John Fields
Professional Circuit Designer

I think "Sediment" would be a better description for TokaMundo,
John. At least that's the sound he made when he was tossed in my troll
bucket weeks ago.

--
Link to my "Computers for disabled Veterans" project website deleted
after threats were telephoned to my church.

Michael A. Terrell
Central Florida

 

[Don Kelly]

"TokaMundo" <TokaMundo@weedizgood.org> wrote in message
news:u670f1df7gqv6i8fdooj5i3c4o0hpdvg0o@4ax.com...

On Tue, 2 Aug 2005 22:58:33 +0000 (UTC), don@manx.misty.com (Don
Klipstein) Gave us:



Going by "High Frequency Resistance", pages 3323-3325 of the 43rd
edition of the "CRC Handbook":

They give a formula X=pi*d*SQR((2*u*f)/rho)*SQR(1000)

u is magnetic permeability, unity for copper.

rho is resistivity in microohm-cm.

They simplify this for copper, to x=10*d*.01071SQR(f)

d is diameter in centimeters, and f is frequency in Hz.

So, for 17 mm diameter copper wire at 60 Hz this "x" is 1.41.

Next is a table that gives ratio of AC resistance to DC resistance as a
function of this "x".

This table has an entry for 1.4, giving AC resistance 1.020 times DC
resistance.


The table I saw shows the AC and DC resistance as being exactly the
same for both.

Your flaw is where you failed to note the topic given in the CRC
handbook.

60 Hz is NOT high frequency... at all.

Try some calculations at 100 kHz and you'll see that those
frequencies down near zero (ie 60Hz) yield very nearly nil difference.
---------------------

In Engineering Electromagnetics, Hayt points out that in a power station a
bus bar for alternating current at 60 Hz much more than 1/3rd of an inch (8
mm) thick is wasteful of copper, and in practice bus bars for heavy AC
current are rarely more than 1/2 inch (12 mm) thick except for mechanical
reasons.
This seems to imply that the bulk of the current is in the outermost 4mm.




This does not mean that conductors, at 60 Hz, which are less than 8mm in
diameter do not show skin effect. 60 Hz AC resistance/DC resistance for
commonly used conductors (say 12 to 6 gauge) may be 1.1 to 1.25 in practice-
this includes skin and proximity effects . However, anyone wanting to do
the math from scratch better be familiar with Bessel functions. Are you?


Skin effect, per se, is not a concern with ACSR power cables as there are a
number of other factors which are more important.

Possibly the approximations for high frequencies are not valid at 60Hz but
this does not mean that skin effect is negligable- except for conductors 000
or higher - provided they are straight. .
The point is that there is no hard and fast "rule" covering all situations
--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------

 

[DBLEXPOSURE]

"Don Kelly" <dhky@shaw.ca> wrote in message
news:dZfIe.110141$s54.2240@pd7tw2no...

"TokaMundo" <TokaMundo@weedizgood.org> wrote in message
news:u670f1df7gqv6i8fdooj5i3c4o0hpdvg0o@4ax.com...
On Tue, 2 Aug 2005 22:58:33 +0000 (UTC), don@manx.misty.com (Don
Klipstein) Gave us:



Going by "High Frequency Resistance", pages 3323-3325 of the 43rd
edition of the "CRC Handbook":

They give a formula X=pi*d*SQR((2*u*f)/rho)*SQR(1000)

u is magnetic permeability, unity for copper.

rho is resistivity in microohm-cm.

They simplify this for copper, to x=10*d*.01071SQR(f)

d is diameter in centimeters, and f is frequency in Hz.

So, for 17 mm diameter copper wire at 60 Hz this "x" is 1.41.

Next is a table that gives ratio of AC resistance to DC resistance as a
function of this "x".

This table has an entry for 1.4, giving AC resistance 1.020 times DC
resistance.


The table I saw shows the AC and DC resistance as being exactly the
same for both.

Your flaw is where you failed to note the topic given in the CRC
handbook.

60 Hz is NOT high frequency... at all.

Try some calculations at 100 kHz and you'll see that those
frequencies down near zero (ie 60Hz) yield very nearly nil difference.
---------------------
In Engineering Electromagnetics, Hayt points out that in a power station a
bus bar for alternating current at 60 Hz much more than 1/3rd of an inch
(8 mm) thick is wasteful of copper, and in practice bus bars for heavy AC
current are rarely more than 1/2 inch (12 mm) thick except for mechanical
reasons.
This seems to imply that the bulk of the current is in the outermost 4mm.




This does not mean that conductors, at 60 Hz, which are less than 8mm in
diameter do not show skin effect. 60 Hz AC resistance/DC resistance for
commonly used conductors (say 12 to 6 gauge) may be 1.1 to 1.25 in
practice- this includes skin and proximity effects . However, anyone
wanting to do the math from scratch better be familiar with Bessel
functions. Are you?


Skin effect, per se, is not a concern with ACSR power cables as there are
a number of other factors which are more important.

Possibly the approximations for high frequencies are not valid at 60Hz but
this does not mean that skin effect is negligable- except for conductors
000 or higher - provided they are straight. .
The point is that there is no hard and fast "rule" covering all situations
--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------

Thanks Don!

I have been watching this thread for days. I like your answer. It's
allways give and take, no hard and fast rules that fit every situation.
And even better yet, You made your point without slamming anybody..

Well Done, Hats off....

 

[Don Kelly]

"TokaMundo" <TokaMundo@weedizgood.org> wrote in message
news:8cdve1tcgsuqvk9maoik4ujpqmnsan0jq6@4ax.com...

On Tue, 02 Aug 2005 10:54:26 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> Gave us:


In big AC transmission lines, there's a complex optimization involving
wire weight, tensile strength, ohmic losses, skin effect, corona
losses, wire cost, and tower spacing/cost.

No shit.

For one thing, they are primarily designed for high tensile strength
as they have to stay mounted through all weather and environmental
conditions.

After that, their resistance is an issue as the primary material has
to be steel for the tensile forces involved. They usually get clad in
Aluminum as copper is too costly for such long runs, and the losses in
using aluminum are little in comparison. This is also the reason that
high voltages are used in long haul transmission lines. The loss
over 2000 feet of line with 120 volts on it is significantly different
than the loss over 2000 feet of line with 20,000 volts on it.
--------

Gee - I thought I^2R loss depended on the current, not the voltage. For a
given power you are right but you didn't state this.
-------------

Corona will become a problem as that line voltage is raised. At
that time line spacing becomes an issue.

Tower spacing is a function of the terrain being traversed. Line
spacing ON a given tower design is a function only of the voltage that
is proposed to be carried, and the total number of conductors.

Skin effect, in these high tension line realms is only an issue if
the idiots that made the wire didn't know how deep to make the
cladding. If the wire is clad to thinly, there will be more loss as
the steel is more resistive, and the wire will heat more as well.
If it is clad too thickly, an unnecessary cost is introduced.
-------

Right -and I have seen ACSR cable with an aluminum depth that exceeds 2cm.
This is unusual and now smaller conductors in bundles (spaced 30-45cm
between conductors ) because of lower inductive reactance and surface fields
that result-notghing to do with skin effect.

This is specifically because the skin depth is so deep at this
frequency, NOT due to it being a thin depth! So in power line cases,
the effect is an issue of how deep the cladding is, not how thin.
-----

Not a big deal. The usual skin depth rules go out the window because of the
magnetic core material and the fact that you have strands of aluminum in
close proximity.
---------

In RF transmission lines, which are typically nickel or silver
plated, it becomes a cost issue, and claddings are made as thin as
possible for a given application frequency. These cases are where one
will see hollow conductors, or plated tube or solids. This is where a
Litz configuration or plated conductor will assist one in design of a
circuit.

At 60Hz, a high voltage step up transformer will have some transfer
efficiency number. At switching frequencies, the same transformer
design (wire turn count wise) will operate better if the primary, and
or secondary have litz wire used in them as the effective resistance
of the winding will be reduced at the higher frequencies.
--------

Note that the equivalent of Litz wire has been used and is used in 60 Hz
generator windings. Wonder why? The individual strands are too small to have
an appreciable skin effect but there is also the proximity effect which can
be more of a problem.
-------------
--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------

 

[Don Kelly]

Skin effect has nothing to do with voltage. Nor is the 15KV level a
"boundary" . It has long been recognised that larger diameter conductors
will reduce surface fields and corona as well as reducing inductance.
However, large diameter conductors are heavy. Initially a copper "barrel
stave" conductor was used but then the idea of a steel core for strength and
aluminum for conductivity replaced this original idea. Skin effect was
reduced and was considered in ther design but basically strength without
loss of conductivity was the basis for practical large diameter conductors.
The bundling of conductors (say 2 to 4 conductors spaced 30-45cm apart) is
an extension of this - effective very large diameter and lower surface
fields and series inductance at a reasonable price and weight savings. This
has nothing to do with skin effect.
--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------
"Dimitrios Tzortzakakis" <dimtzort@otenet.gr> wrote in message
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--
Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ď "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> Ýăńářĺ óôď ěŢíőěá
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"Dimitrios Tzortzakakis" <dimtzort@otenet.gr> wrote in message
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--
Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ď "Alexander" <electricdummy@hotmail.com> Ýăńářĺ óôď ěŢíőěá
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"TimPerry" <timperry@noaspamadelphia.net> schreef in bericht
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"AllTel - Jim Hubbard" <reply@newsgroups.com> wrote in message
news:232f7$42eaf0d2$97d59ba4$23531@ALLTEL.NET...
I am curious about what would happen to an electrical current in 2
situations.....

Assume that you have 2 wires that, when joined, complete a closed
electrical
DC circuit with electrons flowing thusly.....

------------ ============
eeeeeeeeee eeeeeeeeeeeeeee
------------ ============


If you flattened out the end of each wire where they connect ,
would
the
resulting electron paths be more like figure A or Figure B?


neither ... research "skin effect"

Most of the times this just aplies to AC (high frequency) circuits
Or of line-to-line voltage equal or above 220 kV.Therefore transmission
lines of 400 kV are always designed with a double conductor, thus to
reduce
the corona discharge due to skin effect.

Oh boy, you have a 'couple of crossed wires' there.

"Skin effect" is the phenomenon where electric current flow is forced out
from the center of a conductor due to the self-inductance in the
conductor
when carrying AC current. The higher the frequency, the more pronounced
the
current shift to the exterior. It's mostly a problem with high current
situations, even if the voltages are so low that corona discharge is not
a
problem.

"Corona discharge" is *NOT* caused by AC or skin effect. Corona
discharge
is caused by a high voltage gradient in the space around a conductor.
This
is a combination of the voltage applied to the conductor and the
effective
radius of the conductor. A high voltage, or very small effective radius
can
increase the gradient to the point where the air is ionized. Simple
proof
is that corona discharge is a problem with high DC voltage systems as
well
as AC.

Sometimes hollow tubes are used for high frequency power conductors.
This
reduces the weight and cost by eliminating the central part of the
conductor, where 'skin effect' has rendered the impedence high anyway.
So
little admittance is lost for a great savings in material/weight.

And for high voltage systems, multiple parallel conductors are used to
give
a larger 'effective radius', thereby reducing the corona losses.

But the two phenomenon are not related, and the two techniques used are
not
really related.

Yes, but also in voltages >=15 kV there's a signifigant skin effect,
that's
why all transmission conductors are constructed with a steel *core* and an
*aluminium* outer sheath, because the current tends to flow on the skin of
the conductor.I mentioned corona discharge, to bring into evidence the
very
strong electric field around the conductor in very high voltages.
daestrom

 

[TokaMundo]

On Wed, 03 Aug 2005 15:54:26 -0500, John Fields
<jfields@austininstruments.com> Gave us:

---
Sorry, Charlie, there'll still be a temperature gradient across the
diameter of the wire. There has to be, since the surface of the
wire will be radiating heat and being cooled by convection.
---

If it were modeled after the earth, with the heat source in the
center, I would agree. I feel, however, that it is more closely
modeled after Io, which is heated by the magnetic forces of Jupiter,
and more closely approximates an evenly heated body.

In the wire, since the heat is generated throughout the medium via
current flow, even from low currents on up to my cherry red scenario
would show the wire at the same temp from center to outer surface.

The "thermal skin" of the wire that would be slightly cooler due to
surface convection is very thin and beneath it the medium has even
temperature, not a gradient to the center. The reason is that the
surface that you claim to be giving up so much of its heat by
convection isn't that large compared to the whole mass of the wire,
and the source of the heat is throughout the wire's medium.

That's for bare wire and for sheathed or coated wire the containment
is even better.

The word for today is emissivity.

Even though the number is high for bare, matte finished copper, it
still doesn't give up its heat fast enough to have a full gradient
throughout the wire. It would appear as a "skin" when graphed. A
very thin skin.

 

[TokaMundo]

On Wed, 03 Aug 2005 15:54:26 -0500, John Fields
<jfields@austininstruments.com> Gave us:

The current changes the temperature of the wire, but it doesn't
generate the resistance of the wire.

I never said it did.

---
Sure you did. If you go back and read the sentence more carefully,
what you said was:

"and it is that current which generates the heat, or more precisely,
the resistance to said current flow."

Now, if we restructure the sentence in accordance with your
instructions about preciseness, it reads:

"and it is that current which generates the resistance to said
current flow."

Like I said before... I never said that, you fucking asswipe.
You're nothing more than a manipulative lard ass.

which is incorrect.

Yes, you are.

 

[TokaMundo]

On 30 Jul 2005 18:26:41 -0700, "Autymn D. C." <lysdexia@sbcglobal.net>
Gave us:

John Fields wrote:
No, they can only travel at speeds less than the speed of light.

wrong:
http://groups.google.com/group/sci.physics.relativity/browse_frm/thread/5f7c447d531c53f5/f31738a7b007dc8c?lnk=st&rnum=1#f31738a7b007dc8c

Nice.

The condensed form (in a manner of speaking) :-]


http://en.wikipedia.org/wiki/Special_relativity_for_beginners
http://www.fourmilab.ch/etexts/einstein/specrel/www/

 

[TokaMundo]

On Mon, 01 Aug 2005 08:28:25 -0500, John Fields
<jfields@austininstruments.com> Gave us:

I see. Instead of reason, you prefer insult.

I will neither read your "proof" nor will I shut up, and if you
don't like it, you miserable son of a bitch, you can go fuck
yourself.


John Fields
Professional Circuit Designer

THIS GUY IS THE TROLL, FOLKS!!!

 

[TokaMundo]

On Sun, 31 Jul 2005 10:32:46 -0500, "DBLEXPOSURE"
<celstuff@hotmail.com> Gave us:

It is all speculation of course. I have never seen an electron, Have you?

You have never seen lightning? It is an entire stream of them, IN
MOTION. The visible effects are enough. Ever seen "Ball Lightning"?
I suppose ionized air is just the visible result of the electron
passing, and it moves so fast as not to be visible with the human eye,
so what we see is air turned plasma.

Ever had a jolt fire into you? The pain at the entry site tells one
actual movement occurs. The jolt through the body and out the exit
point also concur.

See the photo at alt.binaries.pictures.misc titled "strike"

 

[John Fields]

On Thu, 04 Aug 2005 06:25:43 GMT, TokaMundo
<TokaMundo@weedizgood.org> wrote:

On Wed, 03 Aug 2005 15:54:26 -0500, John Fields
jfields@austininstruments.com> Gave us:

The current changes the temperature of the wire, but it doesn't
generate the resistance of the wire.

I never said it did.

---
Sure you did. If you go back and read the sentence more carefully,
what you said was:

"and it is that current which generates the heat, or more precisely,
the resistance to said current flow."

Now, if we restructure the sentence in accordance with your
instructions about preciseness, it reads:

"and it is that current which generates the resistance to said
current flow."

Like I said before... I never said that, you fucking asswipe.
You're nothing more than a manipulative lard ass.

---
And I've got you dancing to my tune, LOL!
---

which is incorrect.

Yes, you are.

---
Grow up, ya goddam baby.


--
John Fields
Professional Circuit Designer

 

[TokaMundo]

On Thu, 04 Aug 2005 05:34:54 -0500, John Fields
<jfields@austininstruments.com> Gave us:

On Thu, 04 Aug 2005 06:25:43 GMT, TokaMundo
TokaMundo@weedizgood.org> wrote:

On Wed, 03 Aug 2005 15:54:26 -0500, John Fields
jfields@austininstruments.com> Gave us:

The current changes the temperature of the wire, but it doesn't
generate the resistance of the wire.

I never said it did.

---
Sure you did. If you go back and read the sentence more carefully,
what you said was:

"and it is that current which generates the heat, or more precisely,
the resistance to said current flow."

Now, if we restructure the sentence in accordance with your
instructions about preciseness, it reads:

"and it is that current which generates the resistance to said
current flow."

Like I said before... I never said that, you fucking asswipe.
You're nothing more than a manipulative lard ass.

---
And I've got you dancing to my tune, LOL!

Real mature, Johnny. Ranks right up there with the ten year olds.

which is incorrect.

Yes, you are.

---
Grow up, ya goddam baby.

one of my turds has more character than you do, old man.