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jim
Guest

Wed Oct 01, 2003 10:54 pm   



Wade Lippman wrote:

Quote:
Don't even thing about it.

If your #10 gets disconnected, the circuit opens. No problem.
If one strand of your double #12 gets disconnected, your house burns down.
Problem.
I thought he said he had been running it on #12 for years. I guess he

didn't notice his house had burnt down. Poor guy.
--
jim

John Woodgate
Guest

Thu Oct 02, 2003 4:54 am   



I read in sci.engr.electrical.compliance that s <sim.mich_at_cwcom.net>
wrote (in <rFNeb.9$TJ3.5_at_newsfep1-gui.server.ntli.net>) about '30A
wiring advice - a complication?', on Wed, 1 Oct 2003:

Quote:
it isnt two phase!i know that and im a british sparky living and working
in the uk!!it IS single phase,fed from either end of a centre tapped
transfomer,in exactly the same way as our 110 volt transformers we use
for site tools.120v----0v(neutral)----120v.240v end to end,120 end to
middle.if you need to know how this works,think of a sine wave with the
centre line being the centre tap on our transformer!!(rant over). Razz

Well, I'm a Chartered Electrical Engineer, living and working in UK, and
although your detailed explanation is correct, that IS the description
of a two-phase system.

Just as the phase angles between the conductors of a 3-phase system are
120 degrees, so that the three angles add to 360 degrees, the angles
between the phases of a 2-phase system are 180 degrees, adding up to 360
degrees.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

Joe 90
Guest

Thu Oct 02, 2003 7:10 am   



Poor Jim, the #12 was what the manufacturer had installed in the dryer. You
have completely missed the point of my original posting - perhaps I did not
explain it very clearly.

"jim" <email_at_address.net> wrote in message
news:eWIeb.2559$mg.1716_at_twister.nyroc.rr.com...
Quote:
Wade Lippman wrote:

Don't even thing about it.

If your #10 gets disconnected, the circuit opens. No problem.
If one strand of your double #12 gets disconnected, your house burns
down.
Problem.
I thought he said he had been running it on #12 for years. I guess he
didn't notice his house had burnt down. Poor guy.
--
jim


John Woodgate
Guest

Thu Oct 02, 2003 7:28 am   



I read in sci.engr.electrical.compliance that s <sim.mich_at_cwcom.net>
wrote (in <AOOeb.13$kC5.21047_at_newsfep1-win.server.ntli.net>) about '30A
wiring advice - a complication?', on Wed, 1 Oct 2003:

Quote:
im sorry to disagree but i dont consider this to be a true two phase
system,as only one phase is entering the transformer,one leaving.the
centre tap being there for safety/alternate voltage.

If you look at it like that, you get the confusion that troubled the OP.
You have chosen the explanation of the centre-tap to 'prove' your
assertion. But one 120 V supply behaves exactly as a single-phase
supply, and so does the other. When you look at the two together, the
important phase-difference comes into consideration. Your explanation
'hides' the phase-difference.

Quote:
if this were a true
two phase,then it could be fed straight into a squirrel cage motor
without the need of a starting capacitor to phase shift the feild,or am
i missing something quite fundamental here??

Yes, you are missing something. A two-phase system does not create a
rotating magnetic field, as a 3- or higher- phase system can do. So the
motor won't start. The starting capacitor and the second winding DO
create a rotating field.

A 'two-phase' system with 90 degrees between the legs (which is really
half a 4-phase system - the angles must add up to 360 degrees) would
create a rotating field, but it is not easy to derive such a supply from
the public electricity system.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

Beachcomber
Guest

Thu Oct 02, 2003 7:57 am   



Quote:
Perhaps, personally, you are American - no born-and-bred European should
expect to find "gauge" size wire available retail within the EU - and CH
is within, though not of, the EU.

There must be a professional need for wire rated at well over 30A;
consult a friendly professional, or your local equivalent of RS
Components

Many of us Americans are indeed ethno-centric, not realizing what the
standards are or differences in other parts of the word...

However, not all of us are like that and some of us even know that the
AWG stands for American Wire Gauge, and perhaps this might not be the
standard in use for European countries. And some of us do indeed
understand that CH is geographically within the EU (mostly) except
that sometimes a CH is actually an LI.

Beachcomber

Joe 90
Guest

Thu Oct 02, 2003 9:01 am   



It MUST be two phase between the two hot wires, because if it was in one
(the same) phase then the heating element would not heat up.

- +ve 120V
- -
- -
- -
- -
- -ve 120V

+

- +ve 120V
- -
- -
- -
- -
- -ve 120V

= no potential difference between the two hot wires and so no current flow.
Waves are in a single common phase.

- +ve 120V
- -
- -
- - -
- - -
- - -ve 120V

+

- +ve 120V -
- - - -
- - - -
- -
- -
- -ve 120V


= 180 deg phase shift, 240V potential difference at peaks therefore current
flows therefore heater heats up.


"s" <sim.mich_at_cwcom.net> wrote in message
news:rFNeb.9$TJ3.5_at_newsfep1-gui.server.ntli.net...
Quote:
it isnt two phase!i know that and im a british sparky living and working
in
the uk!!it IS single phase,fed from either end of a centre tapped
transfomer,in exactly the same way as our 110 volt transformers we use for
site tools.120v----0v(neutral)----120v.240v end to end,120 end to
middle.if
you need to know how this works,think of a sine wave with the centre line
being the centre tap on our transformer!!(rant over). Razz
"John Woodgate" <jmw_at_jmwa.demon.contraspam.yuk> wrote in message
news:HtKEdNDFyve$EwGN_at_jmwa.demon.co.uk...
I read in sci.engr.electrical.compliance that Joe 90
donot_at_usethisaddress.com> wrote (in <3f7ad039$1_5_at_news.bluewin.ch>)
about '30A wiring advice - a complication?', on Wed, 1 Oct 2003:

The confusion
stems from page 23, of Wiring Simplified 39th edition based on NEC 1999
by Richter and Schwan. It implies that supplies in USA are in single
phase whereas I would have expected a 180deg phase differential which
has indeed been confirmed by a few posters.

Yes, well, you and me both. I have had scorn and derision heaped by US
citizens for describing their system as 'two-phase'. But it IS! (Wink
--
Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go
to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!



Andrew Gabriel
Guest

Thu Oct 02, 2003 10:24 am   



In article <3f7be979_4_at_news.bluewin.ch>,
"Joe 90" <donot_at_usethisaddress.com> writes:
Quote:
It MUST be two phase between the two hot wires, because if it was in one
(the same) phase then the heating element would not heat up.

In terms of maths/physics/engineering you are clearly correct.

In terms of the US electricity supply industry, "2-phase" is
a specific jargon term which applies to only one 2-phase system.
In the UK electricity supply industry, the common US scheme was
called 2-phase (but is long obsolete and was never common).

--
Andrew Gabriel

Spehro Pefhany
Guest

Thu Oct 02, 2003 11:05 am   



On Wed, 1 Oct 2003 06:31:14 -0700, the renowned "s"
<sim.mich_at_cwcom.net> wrote:

Quote:
im sorry to disagree but i dont consider this to be a true two phase
system,as only one phase is entering the transformer,one leaving.the centre
tap being there for safety/alternate voltage.if this were a true two
phase,then it could be fed straight into a squirrel cage motor without the
need of a starting capacitor to phase shift the feild,or am i missing
something quite fundamental here??

Not really. Many of us claim that two linearly dependent voltages
don't represent two distinct "phases", even if one of the
proportionalities happens to be -1. John disagrees.

A two phase supply with conventional 90 (or anything != n * 180, n
is an integer) difference between the phases could be used in motors,
as your comments suggest, or converted by a Scott-T transformer to
make three-phase (or other polyphase) power. Canadian/US residential
power cannot, so those who want to bring an industrial machine tool
into their basement or garage have to use a static, rotary or VFD
phase converter.

This has been discussed before...

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff_at_interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

John McGaw
Guest

Thu Oct 02, 2003 11:12 am   



"Gary Tait" <seesig_at_xxx.yyy> wrote in message
news:1demnv87hbna8862qvtr4mrl9gvh35db7l_at_4ax.com...
Quote:
Whereas On Tue, 30 Sep 2003 20:48:43 -0400, "John McGaw"
nowhere_at_all.xyz> scribbled:
, I thus relpy:
Or is CH simply a convenient posting location?

CH is the TLD for Switzerland.
--
Gary J. Tait . Email is at yahoo.com ; ID:classicsat

It would seem obvious that I knew that already. Why else would my reply
state "Damned difficult to believe that 10-gauge wire is unavailable in
Switzerland."
--
John McGaw
[Knoxville, TN, USA]

Return address will not work. Please
reply in group or through my website:
http://johnmcgaw.com

Lawrence Wasserman
Guest

Thu Oct 02, 2003 1:21 pm   



In article <+odasYAY+6e$EwRJ_at_jmwa.demon.co.uk>,
John Woodgate <jmw_at_jmwa.demon.co.uk> wrote:
<...snipped...>
Quote:

Well, I'm a Chartered Electrical Engineer, living and working in UK, and
although your detailed explanation is correct, that IS the description
of a two-phase system.

Just as the phase angles between the conductors of a 3-phase system are
120 degrees, so that the three angles add to 360 degrees, the angles
between the phases of a 2-phase system are 180 degrees, adding up to 360
degrees.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

That is just so wrong.


--

Larry Wasserman Baltimore, Maryland
lwasserm_at_charm.net

Doug Miller
Guest

Thu Oct 02, 2003 1:28 pm   



In article <1DVeb.13$D93.41288_at_news.abs.net>, lwasserm_at_fellspt.charm.net (Lawrence Wasserman) wrote:
Quote:
In article <+odasYAY+6e$EwRJ_at_jmwa.demon.co.uk>,
John Woodgate <jmw_at_jmwa.demon.co.uk> wrote:
...snipped...

Well, I'm a Chartered Electrical Engineer, living and working in UK, and
although your detailed explanation is correct, that IS the description
of a two-phase system.

Just as the phase angles between the conductors of a 3-phase system are
120 degrees, so that the three angles add to 360 degrees, the angles
between the phases of a 2-phase system are 180 degrees, adding up to 360
degrees.

That is just so wrong.

Maybe you could explain?


--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)

Gary Tait
Guest

Thu Oct 02, 2003 3:25 pm   



Whereas On Thu, 2 Oct 2003 07:12:21 -0400, "John McGaw"
<nowhere_at_all.xyz> scribbled:
, I thus relpy:
Quote:
"Gary Tait" <seesig_at_xxx.yyy> wrote in message
news:1demnv87hbna8862qvtr4mrl9gvh35db7l_at_4ax.com...
Whereas On Tue, 30 Sep 2003 20:48:43 -0400, "John McGaw"
nowhere_at_all.xyz> scribbled:
, I thus relpy:
Or is CH simply a convenient posting location?

CH is the TLD for Switzerland.
--
Gary J. Tait . Email is at yahoo.com ; ID:classicsat

It would seem obvious that I knew that already. Why else would my reply
state "Damned difficult to believe that 10-gauge wire is unavailable in
Switzerland."

I was under the impreddsion you wern't sure if CH was indeed
Switzerland, or some poor country that sold their TLD to companies for
anonymous users.
--
Gary J. Tait . Email is at yahoo.com ; ID:classicsat

H. R. Bob Hofmann
Guest

Thu Oct 02, 2003 3:41 pm   



not_real_at_nospam.xyz (Beachcomber) wrote in message news:<3f7bd671.13280393_at_netnews.comcast.net>...
Quote:
Perhaps, personally, you are American - no born-and-bred European should
expect to find "gauge" size wire available retail within the EU - and CH
is within, though not of, the EU.

There must be a professional need for wire rated at well over 30A;
consult a friendly professional, or your local equivalent of RS
Components

Many of us Americans are indeed ethno-centric, not realizing what the
standards are or differences in other parts of the word...

However, not all of us are like that and some of us even know that the
AWG stands for American Wire Gauge, and perhaps this might not be the
standard in use for European countries. And some of us do indeed
understand that CH is geographically within the EU (mostly) except
that sometimes a CH is actually an LI.

Beachcomber


What is being overlooked here is that the non-USA way of thinking is
not nearly as do it yourself (DIY) as we have here in the USA. Much
more wiring/painting/remodeling, etc is hired out than we are used to
here in the USA. So the availability of things like heavier gauge
wire is really limited. I would suggest looking for a commercial
demolition site and scrounging the wire, if it is not against the
local law to scrounge.

H. R. (Bob) Hofmann

Robert Calvert
Guest

Thu Oct 02, 2003 8:17 pm   



"H. R. Bob Hofmann" <hrhofmann_at_att.net> wrote in message
news:deadaa59.0310020741.63b8536f_at_posting.google.com...
Quote:
not_real_at_nospam.xyz (Beachcomber) wrote in message
news:<3f7bd671.13280393_at_netnews.comcast.net>...
Perhaps, personally, you are American - no born-and-bred European
should
expect to find "gauge" size wire available retail within the EU - and
CH
is within, though not of, the EU.

There must be a professional need for wire rated at well over 30A;
consult a friendly professional, or your local equivalent of RS
Components

Many of us Americans are indeed ethno-centric, not realizing what the
standards are or differences in other parts of the word...

However, not all of us are like that and some of us even know that the
AWG stands for American Wire Gauge, and perhaps this might not be the
standard in use for European countries. And some of us do indeed
understand that CH is geographically within the EU (mostly) except
that sometimes a CH is actually an LI.

Beachcomber


What is being overlooked here is that the non-USA way of thinking is
not nearly as do it yourself (DIY) as we have here in the USA. Much
more wiring/painting/remodeling, etc is hired out than we are used to
here in the USA. So the availability of things like heavier gauge
wire is really limited. I would suggest looking for a commercial
demolition site and scrounging the wire, if it is not against the
local law to scrounge.

Could this mean that status inconsistency is more rampant here in the US

than it is in Europe? After all, in Switzerland, it might be that if my
income is higher than an electrician's income, I would probably hire
somebody to do my electrical work because it wouldn't be worth my time to do
it myself. And if my income is lower than an electrician's income, I
probably wouldn't be able to do what an electrician can do - in which case I
would probably hire this work out anyway. In the US, on the other hand, it's
not inconceivable that there are many more people who can do what an
electrician can do but who don't make as much money as an electrician. In
such an environment, you would probably find many more do-it-yourselfers.

Just a thought. :-)

Robert

Dr John Stockton
Guest

Thu Oct 02, 2003 8:25 pm   



JRS: In article <G$ck54AdO9e$Ewn9_at_jmwa.demon.co.uk>, seen in news:sci.e
ngr.electrical.compliance, John Woodgate <jmw_at_jmwa.demon.contraspam.yuk>
posted at Thu, 2 Oct 2003 08:28:29 :-
Quote:

A 'two-phase' system with 90 degrees between the legs (which is really
half a 4-phase system - the angles must add up to 360 degrees) would
create a rotating field, but it is not easy to derive such a supply from
the public electricity system.

If you count 3-phase as public : It is I believe delivered in the UK as
star, with a neutral near ground.

Connect a 1:1 transformer to one leg, neutral to live wire.
Connect a Root3:1 transformer between the other two live wires.

ISTM that one then gets two outputs in quadrature, of equal magnitude.

Admittedly it is impractical to use an integer multiple of Root3 turns,
but 97:56 is within 1 in 10^4.

<URL:http://www.merlyn.demon.co.uk/js-demos.htm#App>, enter Math.sqrt(3)

Note, though, that the three supply phases are not equally loaded, and
I've not worked out whether there is neutral current. Loading could be
made to balance with an auxiliary two-input transformer, driven from the
second two legs, and connected to buck/boost the output of the first
transformer, I think.

Untested.

--
John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 IE 4
<URL:http://jibbering.com/faq/> Jim Ley's FAQ for news:comp.lang.javascript
<URL:http://www.merlyn.demon.co.uk/js-index.htm> JS maths, dates, sources.
<URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/JS/&c., FAQ topics, links.

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