Stupid question of the day....

[Alexander]

"John Fields" <jfields@austininstruments.com> schreef in bericht
news:enate1tkhlkv8gajkdjbjq7u3guvkkokno@4ax.com...

On Mon, 1 Aug 2005 18:23:25 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


Sometimes you have something like Aluminium inside (for the weight) and
Cupper on the outside for conductivity. Due to the Skin Effect this is
where
the most (AC) current will flow.
On some application I have even seen Cu on the inside and Au on the
outside,
my guess there is at least one other material between the two for obvious
reasons.

Really? The reasoning for that layering doesn't seem obvious to me,
so would you mind explaining it in greater detail?

--
John Fields
Professional Circuit Designer

If you connect Au to Cu and put a Current through it, for best results AC,
the Cu starts corroding at the transistion from Cu to Au. This is always the
case when putting to metals together, the greater the difference between the
metals the faster the corroding will be.

 

[Alexander]

"Alexander" <electricdummy@hotmail.com> schreef in bericht
news:dcmtj7$a9d$1@news4.zwoll1.ov.home.nl...

"John Fields" <jfields@austininstruments.com> schreef in bericht
news:enate1tkhlkv8gajkdjbjq7u3guvkkokno@4ax.com...
On Mon, 1 Aug 2005 18:23:25 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


Sometimes you have something like Aluminium inside (for the weight) and
Cupper on the outside for conductivity. Due to the Skin Effect this is
where
the most (AC) current will flow.
On some application I have even seen Cu on the inside and Au on the
outside,
my guess there is at least one other material between the two for obvious
reasons.

Really? The reasoning for that layering doesn't seem obvious to me,
so would you mind explaining it in greater detail?

--
John Fields
Professional Circuit Designer

If you connect Au to Cu and put a Current through it, for best results AC,
the Cu starts corroding at the transistion from Cu to Au. This is always
the case when putting to metals together, the greater the difference
between the metals the faster the corroding will be.

This is also the reason why silver and gold contacts should never be

soldered with normal Sn63Pb37 solderwire

 

[John Fields]

On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
<electricdummy@hotmail.com> wrote:

If you connect Au to Cu and put a Current through it, for best results AC,
the Cu starts corroding at the transistion from Cu to Au. This is always the
case when putting to metals together, the greater the difference between the
metals the faster the corroding will be.

---
That's not true.

--
John Fields
Professional Circuit Designer

 

[Dimitrios Tzortzakakis]

--
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
news:XmzHe.1962$Rc6.702@twister.nyroc.rr.com...

"Dimitrios Tzortzakakis" <dimtzort@otenet.gr> wrote in message
news:dcl731$u0$1@usenet.otenet.gr...


--
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
news:dcfqoa$dbo$1@news1.zwoll1.ov.home.nl...

"TimPerry" <timperry@noaspamadelphia.net> schreef in bericht
news:WrqdndPloplTh3bfRVn-3w@adelphia.com...

"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

 

[Alexander]

Op [GMT+1=CET], hakte John Fields op ons in met:

On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


If you connect Au to Cu and put a Current through it, for best
results AC, the Cu starts corroding at the transistion from Cu to
Au. This is always the case when putting to metals together, the
greater the difference between the metals the faster the corroding
will be.

---
That's not true.
You're right it needs also an electrlyt which is most of the times present.

 

[John Larkin]

On Tue, 02 Aug 2005 02:57:11 GMT, TokaMundo <TokaMundo@weedizgood.org>
wrote:

Of course, in an AC line, the current density isn't uniform, so neither is
the heat generation. So when it comes to skin effect, it tends to lower the
peak, centerline temperature.

Now, given that both copper and aluminum are excellent heat conductors, it
might be interesting to calculate how big a temperature profile could be
expected, and from this calculate the variation in resistivity.

I suspect the work has been done before, and that the difference is rather
modest for all but the largest cylindrical conductors.

For AC at this frequency there is nil skin effect.

Not nil. Do the math.

John

 

[DBLEXPOSURE]

"John Fields" <jfields@austininstruments.com> wrote in message
news:4ofue1lca6tpqat9iqvepk6dhplv1v9335@4ax.com...

On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


If you connect Au to Cu and put a Current through it, for best results AC,
the Cu starts corroding at the transistion from Cu to Au. This is always
the
case when putting to metals together, the greater the difference between
the
metals the faster the corroding will be.

---
That's not true.

--
John Fields
Professional Circuit Designer

Firstly, Aluminium is Al not Au. Au is gold. You are speaking of
aluminium and coper?

Galvanic Corrosion Is possible when Al and Cu are in contact with one and
other. If I recal correctly a dialectric such as water needs to be present.
Cathodic protection, (electric current) can be used to slow or stop this
proccess. I Imagine reversing the polarity may speed it up. Aluminium is
the "Less Nobel" of the two metals so I would imagine that it would be the
one to corrode.

 

[Alexander]

Op [GMT+1=CET], hakte DBLEXPOSURE op ons in met:

"John Fields" <jfields@austininstruments.com> wrote in message
news:4ofue1lca6tpqat9iqvepk6dhplv1v9335@4ax.com...
On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


If you connect Au to Cu and put a Current through it, for best
results AC, the Cu starts corroding at the transistion from Cu to
Au. This is always the
case when putting to metals together, the greater the difference
between the
metals the faster the corroding will be.

---
That's not true.

--
John Fields
Professional Circuit Designer

Firstly, Aluminium is Al not Au. Au is gold. You are speaking of
aluminium and coper?

Galvanic Corrosion Is possible when Al and Cu are in contact with one
and other. If I recal correctly a dialectric such as water needs to
be present. Cathodic protection, (electric current) can be used to
slow or stop this proccess. I Imagine reversing the polarity may
speed it up. Aluminium is the "Less Nobel" of the two metals so I
would imagine that it would be the one to corrode.

Correct I also added the remark of the diëlectricum to the discussion.
And your remark about Aluminium is correct, however as stated in some
applications I have seen an Copper core and an Gold (aurum) shell. And since
the combination gold-copper is worse then the well known combination
aluminium-copper.

But at least ThanX for confirming my statement and not saying its not true
without giving a reason as someone else did.

 

[TokaMundo]

On Mon, 01 Aug 2005 20:21:31 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> Gave us:

On Tue, 02 Aug 2005 03:00:06 GMT, TokaMundo <TokaMundo@weedizgood.org
wrote:


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. At 60 Hz, copper skin depth is about 0.85 cm.

Did you even look at that number? That is 8.5 mm!

No? OK. So for all practical purposes that do not have 20 cm wire
involved (ie any normal residential application) there is NO skin
effect! Where in everyday life does a person use wire that has a
diameter greater than 8.5 mm that would present anything other than
100% current density in the conductor? The wave is just too slow for
anything other than full propagation. Hell, even a 25kW transformer
won't see any difference.

In ohms per foot DC or AC at 60Hz the value is the same for all wire
diameters that have a gauge number.

Before any difference could even be noted, the wired diameter would
have to be over 16 mm.

What part of the word negligible, or not of any effect do you not
understand?

http://www.bcae1.com/trnsfrmr.htm

If you'll read down the page to the skin depth calculators, you'll
see that the ohms per foot (the only value that matters here) is the
same for any gauge wire put into the calculator fields.

 

[TokaMundo]

On Mon, 01 Aug 2005 21:28:10 -0700, Don Bowey <dbowey@comcast.net>
Gave us:

On 8/1/05 8:00 PM, in article vdote1tb8oed91mpoiqsa0pag4s4lclrnm@4ax.com,
"TokaMundo" <TokaMundo@weedizgood.org> wrote:

On Tue, 02 Aug 2005 00:45:43 GMT, "daestrom"
daestrom@NO_SPAM_HEREtwcny.rr.com> Gave us:


"Dimitrios Tzortzakakis" <dimtzort@otenet.gr> wrote in message
news:dcl731$u0$1@usenet.otenet.gr...


--
Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "Alexander" <electricdummy@hotmail.com> ?????? ??? ??????
news:dcfqoa$dbo$1@news1.zwoll1.ov.home.nl...

"TimPerry" <timperry@noaspamadelphia.net> schreef in bericht
news:WrqdndPloplTh3bfRVn-3w@adelphia.com...

"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.

It becomes more prevalent as frequency goes up, not current.


"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.

Define "VERY." Is that higher than Very and very?

Your logic varies.

Skin effect is measurable in cables at as low as 100 kHz.

Don

Tell us, guru don, where does 100kHz get used as an AC power line
frequency?

 

[TokaMundo]

On Tue, 02 Aug 2005 04:41:38 -0500, John Fields
<jfields@austininstruments.com> Gave us:

On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


If you connect Au to Cu and put a Current through it, for best results AC,
the Cu starts corroding at the transistion from Cu to Au. This is always the
case when putting to metals together, the greater the difference between the
metals the faster the corroding will be.

---
That's not true.

It's called galvanic reaction.

The Navy seems to think it's real. Does that make you an idiot?

 

[TokaMundo]

On Tue, 2 Aug 2005 15:33:21 +0300, "Dimitrios Tzortzakakis"
<dimtzort@otenet.gr> Gave us:

Yes, but also in voltages >=15 kV there's a signifigant skin effect,

Wrong! Skin effect is a function of frequency, not voltage. The
reason YOU think there is a significant skin effect is likely due to
the method at which your "15kV" source was generated.

That being likely a high frequency switcher or oscillator.

that's
why all transmission conductors are constructed with a steel *core* and an
*aluminium* outer sheath,

No, it isn't. FREQUENCY is the reason. The other reason steel
cores are used is due to the fact that transmission lines are
typically hung from between two points separated by some great
distance such that the wire itself needs to be able to support the
weight of itself. The steel cores are there to increase the tensile
strength of the overall transmission line. This is a reference to
high frequency RF transmission lines. For power lines, steel is used
for the same, tensile increasing reason. The cladding is used to
reduce the ohms per foot of the strand. At 60Hz, however, the skin
effect hovers near NIL.

because the current tends to flow on the skin of
the conductor.

That is 100% dependent upon frequency.

http://www.bcae1.com/trnsfrmr.htm

I mentioned corona discharge, to bring into evidence the very
strong electric field around the conductor in very high voltages.

Corona is a function of voltage and the capacity for air to ionize.
How much corona is on a wire in oil that carries a high voltage AC or
DC? Same wire in air?

Electric fields increase with current in a wire. Look at a quarter
shrinker. Low voltage, high current, huge field.

 

[TokaMundo]

On Tue, 02 Aug 2005 08:06:25 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> Gave us:

On Tue, 02 Aug 2005 02:57:11 GMT, TokaMundo <TokaMundo@weedizgood.org
wrote:



Of course, in an AC line, the current density isn't uniform, so neither is
the heat generation. So when it comes to skin effect, it tends to lower the
peak, centerline temperature.

Now, given that both copper and aluminum are excellent heat conductors, it
might be interesting to calculate how big a temperature profile could be
expected, and from this calculate the variation in resistivity.

I suspect the work has been done before, and that the difference is rather
modest for all but the largest cylindrical conductors.

For AC at this frequency there is nil skin effect.


Not nil. Do the math.

Very much so as close to nil as it gets. Review the math.

http://www.bcae1.com/trnsfrmr.htm

That's just one source.

 

[Owamanga]

On Tue, 02 Aug 2005 17:40:35 GMT, TokaMundo <TokaMundo@weedizgood.org>
wrote:

Corona is a function of voltage and the capacity for air to ionize.

Wow, and I thought it was a Mexican beer that tastes so bad you have
to add lime to it before consumption.

--
Owamanga!
http://www.pbase.com/owamanga

 

[John Larkin]

On Tue, 02 Aug 2005 17:24:34 GMT, TokaMundo <TokaMundo@weedizgood.org>
wrote:

On Mon, 01 Aug 2005 20:21:31 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> Gave us:

On Tue, 02 Aug 2005 03:00:06 GMT, TokaMundo <TokaMundo@weedizgood.org
wrote:


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. At 60 Hz, copper skin depth is about 0.85 cm.

Did you even look at that number? That is 8.5 mm!

Not only did I look at it, but I calculated it, and typed it.

No? OK. So for all practical purposes that do not have 20 cm wire
involved (ie any normal residential application) there is NO skin
effect! Where in everyday life does a person use wire that has a
diameter greater than 8.5 mm that would present anything other than
100% current density in the conductor? The wave is just too slow for
anything other than full propagation. Hell, even a 25kW transformer
won't see any difference.

I just bought a building that has 3-phase, 800-amp service, and skin
effect certainly has affected the sizing of the main feeder wires. And
I work with people who build gigawatt 60 Hz power plants and jumbo-jet
400 Hz power systems. That's my "everyday life."

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.

In ohms per foot DC or AC at 60Hz the value is the same for all wire
diameters that have a gauge number.

Before any difference could even be noted, the wired diameter would
have to be over 16 mm.

Not so. At 0.85 cm depth, current density is down to 1/e (ie, only
0.37 of) the surface density. That's pretty significant.

What part of the word negligible, or not of any effect do you not
understand?

I'm an engineer, so I consider something to be "negligable" if I can
demonstrate, quantitatively, that it doesn't matter enough to affect a
system. 37% is therefore worth a second look.

To speak in your style, what part of "doing the math" do you not
understand?

John

 

[TokaMundo]

On Tue, 02 Aug 2005 17:43:16 GMT, Owamanga
<owamanga-not-this-bit@hotmail.com> Gave us:

On Tue, 02 Aug 2005 17:40:35 GMT, TokaMundo <TokaMundo@weedizgood.org
wrote:

Corona is a function of voltage and the capacity for air to ionize.

Wow, and I thought it was a Mexican beer that tastes so bad you have
to add lime to it before consumption.

And they have the nerve to call it a "specialty beer" here in So
Cal.

Just so the idiots can charge more for less!

Talk about misnomers!

Give me a Sam Adams or Chimay Gold ANYDAY!

Bass Ale... anything!

Sheesh Coors' "Killian's Red" is better than that Mexican crap!

 

[TokaMundo]

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

Before any difference could even be noted, the wired diameter would
have to be over 16 mm.

Not so. At 0.85 cm depth, current density is down to 1/e (ie, only
0.37 of) the surface density. That's pretty significant.

0.85cm is 8.5 mm. That means that the wire has to be bigger than
that number as a radius before the current flow anywhere else besides
the entire wire.

So, again, if the wire is less than 17mm in diameter, there will be
no skin effect involved. You may note some other effects, but skin
effect won't be one of them.

 

[TokaMundo]

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

What part of the word negligible, or not of any effect do you not
understand?

I'm an engineer, so I consider something to be "negligable" if I can
demonstrate, quantitatively, that it doesn't matter enough to affect a
system.

No shit.

37% is therefore worth a second look.

Your application of your "math" is what needs a second look.

To speak in your style, what part of "doing the math" do you not
understand?

What part of "you did the math wrong" do you not understand?

Before it would make a difference, the wire will have to be pretty
big (over 17mm diameter) , and before it will make a 37% difference,
it would have to be bigger still! Real simple math, there.

 

[DBLEXPOSURE]

"Alexander" <electricdummy@hotmail.com> wrote in message
news:dco8pe$4nl$1@news2.zwoll1.ov.home.nl...

, hakte DBLEXPOSURE op ons in met:

"John Fields" <jfields@austininstruments.com> wrote in message
news:4ofue1lca6tpqat9iqvepk6dhplv1v9335@4ax.com...
On Tue, 2 Aug 2005 06:42:29 +0200, "Alexander"
electricdummy@hotmail.com> wrote:


If you connect Au to Cu and put a Current through it, for best
results AC, the Cu starts corroding at the transistion from Cu to
Au. This is always the
case when putting to metals together, the greater the difference
between the
metals the faster the corroding will be.

---
That's not true.

--
John Fields
Professional Circuit Designer

Firstly, Aluminium is Al not Au. Au is gold. You are speaking of
aluminium and coper?

Galvanic Corrosion Is possible when Al and Cu are in contact with one
and other. If I recal correctly a dialectric such as water needs to
be present. Cathodic protection, (electric current) can be used to
slow or stop this proccess. I Imagine reversing the polarity may
speed it up. Aluminium is the "Less Nobel" of the two metals so I
would imagine that it would be the one to corrode.

Correct I also added the remark of the diëlectricum to the discussion.
And your remark about Aluminium is correct, however as stated in some
applications I have seen an Copper core and an Gold (aurum) shell. And
since the combination gold-copper is worse then the well known combination
aluminium-copper.

But at least ThanX for confirming my statement and not saying its not true
without giving a reason as someone else did.

Your welcome, I thought you deserved a respectful reply...

 

[TokaMundo]

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.

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.

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.

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.