sci.electronics.repair@googlegroups.com

Today's topics:

* Two phases or not? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
* Type K themorcouple - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/e7b17a33b38bf2d5?hl=en
* Pet hates ? - 4 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/e7925b5c2233e9ec?hl=en

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TOPIC: Two phases or not?
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
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== 1 of 2 ==
Date: Sat, Jan 22 2011 10:39 pm
From: Bob AZ

>
> And of course there's 3-phase power, widely used today.
>
> The problem is this: several people, myself included, contend that the
> two "legs" of power produced by a center-tapped transformer do, in fact,
> constitute two separate phases of power, 180° apart. (This is how
> household power is delivered in North America, with a step-down xfmr at
> the power pole delivering 240 volts in the form of 120-0-120.)
>

David et al

A specific that many are not aware of and are left wondering when
discussed is the following.

The transformer that feeds your home and many small businesses has a
single phase impressed across the primary winding. Usually called a HV
winding. No big deal for this discussion. The "secondary winding" is
actually two identical windings. Sometimes called tertiary windings.
But this term usually leaves most on the dark. Not a commonly used
term since we don't usually get into the actual electrical and/or
mechanical construction of transformers, let alone the ones feeding
our homes. To most they are simply an unknown on the pole in the alley
or in a pedestal box in the front yard of residential houses.

Back to the actual transformer. A primary winding and two identical
secondary windings. The seondary windings are wound identically within
and about the primary winding. Well insulated of course. The primary
winding impresses each winding identically, in this case, 120 volts.
So the operation of the secondary windings are identical.

The secondary windings are connected in an addtive fashion to give 240
volts across the ends of the connected windings. Their common
terminal, internally connected, is sometimes thought of as a "center"
tap. But the windings are not actually centertapped. They are only
connected in a additive fashion to give the desired 240 volts. 120
volts is of course is simply a connection to a hot lead and the
common terminal. When both windings are utilized we end up with two
"hot" leads which are used for the 120 volt loads. The same additive
principle could be used to give perhaps 360 or 480 volts.

But in no case, with the information presented here, is there any
method or device utilized to give any additional phases. One or two or
more. The hot legs are simply the same phase, transformed as needed,
added within the transformer, with the resultant two hot legs, 180
degrees out of phase with each other. Were the windings connected "in
phase" the available voltage would be 50% and the power, amps,
available doubled.

Three phase distribution starts with a generator with 3 sets of
windings that is distributed as three phase and utuilzed as needed.
Residential as this discussion continues, and large users with many
motor (inductive) loadings commonly found in motors 5 or more HP. The
5 HP figure is an industry norm that takes advantage of the inherent
advantages of 3 phase. Mainly distribution costs and three phase
motors.

Disclaimer: Transformers, power distribution, are not my usual area of
expertise. This would be several different lifelong careers followed
by others. I simply deal with it on an almost daily basis and have for
over 50 years.

Enough for a long day.

Bob AZ

== 2 of 2 ==
Date: Sat, Jan 22 2011 10:49 pm
From: "Phil Allison"

"Bob AZ"

( snip tedious drivel)

But in no case, with the information presented here, is there any
method or device utilized to give any additional phases. One or two or
more. The hot legs are simply the same phase, transformed as needed,
added within the transformer, with the resultant two hot legs, 180
degrees out of phase with each other.

** A really beautiful example of "double think" if I ever saw one.

Three phase distribution starts with a generator with 3 sets of
windings that is distributed as three phase and utuilzed as needed.

** And if it had only 2 windings instead of 3 ??

Two AC waves would be produced simultaneously, remaining always 180 degrees
apart in phase and be completely * indistinguishable * from any other means
of creating the same situation.

..... Phil

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TOPIC: Type K themorcouple
http://groups.google.com/group/sci.electronics.repair/t/e7b17a33b38bf2d5?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 22 2011 11:47 pm
From: Smitty Two

In article <4d3b38b1$0$7528$bbae4d71@news.suddenlink.net>,
Jeffrey Angus <jangus@suddenlink.net> wrote:

> Anybody have a Type K thermocouple laying about they don't need?
> Even if it's just a chunk of Type-wire. I can weld the end if
> need be.
>
> THanks
> Jeff

I've got the wire.

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TOPIC: Pet hates ?
http://groups.google.com/group/sci.electronics.repair/t/e7925b5c2233e9ec?hl=en
==============================================================================

== 1 of 4 ==
Date: Sun, Jan 23 2011 12:02 am
From: Smitty Two

In article <4d3b9067$0$2378$822641b3@news.adtechcomputers.com>,
David Nebenzahl <nobody@but.us.chickens> wrote:

> On 1/21/2011 5:43 PM Arfa Daily spake thus:
>
> > He was in sunny Caffy-lornia ... Costa Mesa in Orange County, a few miles
> > down the Interstate from LA
>
> OK, Arf, a small lesson in regional US dialects, free of charge:
>
> Nobody here in "Cal-ee-fonia", as our recently departed
> Governator/Gropenator called it, calls them "interstates", even though
> they are, in fact, interstate highways. Some folks back east may call
> them that, though I'm not sure (I've heard them referred to as
> "turnpikes" in some places). One wonders whether some LA residents even
> know what an "interstate" is ...
>
> In any case, just in case you actually visit Caleefonia sometime in the
> near future, you should also be aware of an important difference in
> usage between SoCal (basically El-Lay and environs) and NoCal (San
> Francisco and thereabouts). Down there, they don't use *any* noun for a
> road (highway, interstate, etc.), but they do use articles with the road
> number, as in "the 405", "the 101", etc.
>
> But beware: up here in the Beige Area, where we like to think we're so
> much superior to our SoCal cousins, we never use the article, saying
> instead "take 80 to get to Berkeley" or "take 101 to 280 to 17 to get
> down to Santa Cruz". (One can easily spot newcomers to San Francisco who
> refer to "the 80" or "the 101". That's just SO wrong!)

I don't think Arfa is going to "blend" whether he uses your terminology
or not, and I doubt that's his objective. But you wrote an awful lot of
words without using "freeway," which is what we call the 101 here, and
is the most common word for "interstate highway" throughout the midwest,
as well. I'm not going to say unequivocally that it's widely used all
over the U.S., because I don't know for sure, but I'd bet money on it.

In cities with many freeways, they have to use more specific terms, but
when there's only one, who needs a number?

BTW, everyone I know in LA doesn't use numbers at all, but names that
are meaningless to outsiders even if they have a map: "Ventura freeway,"
"Hollywood freeway," "Pasadena freeway," etc.

== 2 of 4 ==
Date: Sun, Jan 23 2011 12:13 am
From: David Nebenzahl

On 1/23/2011 12:02 AM Smitty Two spake thus:

> In article <4d3b9067$0$2378$822641b3@news.adtechcomputers.com>,
> David Nebenzahl <nobody@but.us.chickens> wrote:
>
>> But beware: up here in the Beige Area, where we like to think we're so
>> much superior to our SoCal cousins, we never use the article, saying
>> instead "take 80 to get to Berkeley" or "take 101 to 280 to 17 to get
>> down to Santa Cruz". (One can easily spot newcomers to San Francisco who
>> refer to "the 80" or "the 101". That's just SO wrong!)
>
> I don't think Arfa is going to "blend" whether he uses your terminology
> or not, and I doubt that's his objective. But you wrote an awful lot of
> words without using "freeway," which is what we call the 101 here, and
> is the most common word for "interstate highway" throughout the midwest,
> as well.

Yup, my bad; thought of it shortly after clicking "Send", of course.

> BTW, everyone I know in LA doesn't use numbers at all, but names that
> are meaningless to outsiders even if they have a map: "Ventura freeway,"
> "Hollywood freeway," "Pasadena freeway," etc.

Forgot about that too. Our freeways also have names, but they're
(mostly) unused: one occasionally hears 880 called "the Nimitz" or 80
"the Eastshore", but more often not.

Then of course there's Johnny Carson's old favorite, the "Slauson
Cutoff" ...

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 3 of 4 ==
Date: Sun, Jan 23 2011 12:44 am
From: "Geoffrey S. Mendelson"

David Nebenzahl wrote:
> Then of course there's Johnny Carson's old favorite, the "Slauson
> Cutoff" ...

My favorite Israeli highway story is about route 1, the road from Jerusalem
to Tel Aviv. Although Tel Aviv is a little over 100 years old, the original
city of Jaffa (aka Yaffo) has been there since biblical times, and this is
at least in spirit, that road.

Meanwhile Israeli's are big fans of acronyms. The Hebrew abreviation of
airport is N T and the main one here is named Ben Gurion. So the name of
the airport on road signs is written in Hebrew NTBG, which is pronnounced
"not bog".

About fifteen years ago in a refurbishment of route 1, someone decided
that there should be English signs on the road for tourists who could not
read Hebrew. So a set of signs went up for the airport "NATBAG 1km". :-)

Yes, they were later changed to "Ben Gurion Airport 1km".

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

== 4 of 4 ==
Date: Sun, Jan 23 2011 12:59 am
From: "N_Cook"

Geoffrey S. Mendelson <gsm@mendelson.com> wrote in message
news:slrnijnqfo.euo.gsm@cable.mendelson.com...
> David Nebenzahl wrote:
> > Then of course there's Johnny Carson's old favorite, the "Slauson
> > Cutoff" ...
>
> My favorite Israeli highway story is about route 1, the road from
Jerusalem
> to Tel Aviv. Although Tel Aviv is a little over 100 years old, the
original
> city of Jaffa (aka Yaffo) has been there since biblical times, and this is
> at least in spirit, that road.
>
> Meanwhile Israeli's are big fans of acronyms. The Hebrew abreviation of
> airport is N T and the main one here is named Ben Gurion. So the name of
> the airport on road signs is written in Hebrew NTBG, which is pronnounced
> "not bog".
>
> About fifteen years ago in a refurbishment of route 1, someone decided
> that there should be English signs on the road for tourists who could not
> read Hebrew. So a set of signs went up for the airport "NATBAG 1km". :-)
>
> Yes, they were later changed to "Ben Gurion Airport 1km".
>
> Geoff.
>
> --
> Geoffrey S. Mendelson N3OWJ/4X1GM
> Those who cannot remember the past are condemned to misquote it.

I wonder what visitors to the UK make of official roadsigns, imagining a
country infested with triffids , that say
Large Plant Crossing

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