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Re: Odd wiring in tube ampmschematics

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the same & opposite current, resulting in nearly zero magnetic field. Pacem
akers, like any life-critical medical equipment, are designed & tested to m
eet harsh real-world conditions & keep going.

Nope:

The neutral carries the "difference current" in the legs of a split phase s
ystem.  It can be 180 or -180 out of phase (Said for ease of understanding)
.  It can also be zero, but not likely,

The "difference current" is more accurate.  While voltage is usually sinuso
idal, current doesn't have to be.  Voltage is what's regulated. inductive l
oads are one matter, but laptop switching power supplies is another.


Re: Odd wiring in tube ampmschematics
Ron D. wrote:

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y the same & opposite current, resulting in nearly zero magnetic field. Pac
emakers, like any life-critical medical equipment, are designed & tested to
 meet harsh real-world conditions & keep going.
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** Fraid it is a yep.

Any mains appliance returns the same current down the neutral conductor it  
drew from the active.  This mean very little mag field is generated by the  
appliance's own lead, assuming the two wires are closely paired or twisted.
  



...  Phil  

Re: Odd wiring in tube ampmschematics
snipped-for-privacy@gmail.com says...
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I think you all are compairing apples and oranges.

One is thinking of a 240 volt system with 2 hots and the neutral, whrere  
the neutral can have almost any ammount of current on it up to being  
equal to what one side of the hot is using (120 volt devices).

Phil and the other are probably talking about a 120 volt device that has  
only a hot and neutral. Which in that case the neutral must have the  
same ammount of cuttent as the hot wire, unless there is a problem.


Re: Odd wiring in tube ampmschematics
On 12/9/18 3:14 PM, Ralph Mowery wrote:
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This is one of fallacies here in Ranger.
Around here, the thought is the Neutral to the breaker panel from
the meter can be smaller because it's not going to carry ALL of the
current because there will be an offsetting current from the other
hot leg.

They also tend to under size everything, because, you know, copper
is expensive. For example, my house has a 200 Amp service.
That should be #000 on all three legs and #4 for the ground.
When I got here, it was two #4 on the hots, #6 on the neutral and
#10 for the ground.
That was one of the first things I fixed.


--  
"I am a river to my people."
Jeff-1.0
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Re: Odd wiring in tube ampmschematics
snipped-for-privacy@att.net says...
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Well you do not have to worry about ice forming on the power wires.  I  
think one chart showed about 105 deg C for the temperature rise with the  
# 4 wire at around 200 amps.



Re: Odd wiring in tube ampmschematics
On 10/12/18 8:14 am, Ralph Mowery wrote:
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Phil lives in Sydney. We use 240V single phase wiring, with a single hot  
and a single neutral grounded at the panel. The RCD protection trips if  
the currents on hot and neutral differ, even by milliamps for milliseconds.

Some (few) buildings have two separate 240V phases wired to different  
circuits inside the house, but nothing gets connected between the phases.

Clifford Heath.

Re: Odd wiring in tube ampmschematics
Ralph Mowery wrote:

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** If a 240V load is connected across the two phases, then the current is each wire is the same.  

The principle is simple: a current carrying loop that is closed down on itself ( ie the wires are paralleled) or twisted cannot radiate a mag field.


....   Phil  

Re: Odd wiring in tube ampmschematics
On Sunday, 9 December 2018 19:14:44 UTC, Ron D.  wrote:
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y the same & opposite current, resulting in nearly zero magnetic field. Pac
emakers, like any life-critical medical equipment, are designed & tested to
 meet harsh real-world conditions & keep going.
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 system.  It can be 180 or -180 out of phase (Said for ease of understandin
g).  It can also be zero, but not likely,
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soidal, current doesn't have to be.  Voltage is what's regulated. inductive
 loads are one matter, but laptop switching power supplies is another.


I think you'll find house sockets are wired single phase.


NT

Re: Odd wiring in tube ampmschematics
On 12/10/18 4:04 AM, snipped-for-privacy@gmail.com wrote:
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Actually, the term "Split Phase" is accurate.
The source is a center tapped 240 volt winding.
-180 0 +180 degrees.
Either side to center (neutral) is 120v, and across both sides (hot)
is 240v.
The usual problem is when people insist on calling it 2-phase due to
the +/- nature of it.
It is not, the primary is single phase.

The real problem occurs in a 3-phase Wye system.
A-N, B-N and C-N are each 120 volts. Until someone who doesn't know
how it works, takes A-B and tells the consumer it's 240v. And then
typically table saws go up in flames, because they REALLY do no like
running at 208 volts with a 120 instead of 180 phase shift across
the windings.




--  
"I am a river to my people."
Jeff-1.0
We've slightly trimmed the long signature. Click to see the full one.
Re: Odd wiring in tube ampmschematics
120*(3^^0.5) gives 207V, not 240.


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Re: Odd wiring in tube ampmschematics
On 12/10/18 6:01 AM, Look165 wrote:
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207.84 or commonly called 208.

I said uneducated electricians THINK that two 120v phases
running 120 degrees instead of 180 degrees apart equals
240 volts.

As a service manager in a tool store, I had to explain that
running a 5 HP table saw motor on 208 volts was NOT covered
under warranty and they should make their "electrician" pay
for the repairs.

--  
"I am a river to my people."
Jeff-1.0
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Re: Odd wiring in tube ampmschematics
On Monday, 10 December 2018 11:42:17 UTC, Fox's Mercantile  wrote:
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ry the same & opposite current, resulting in nearly zero magnetic field. Pa
cemakers, like any life-critical medical equipment, are designed & tested t
o meet harsh real-world conditions & keep going.
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ase system.  It can be 180 or -180 out of phase (Said for ease of understan
ding).  It can also be zero, but not likely,
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inusoidal, current doesn't have to be.  Voltage is what's regulated. induct
ive loads are one matter, but laptop switching power supplies is another.
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3 phase has an angle between each phase of 360/3 = 120 degrees.
2 phase has an angle between each phase of 360/2 = 180 degrees. And that'
s what you have with the US domestic 120/240 system.


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Naturally some people don't understand some things, nothing new there.


NT

Re: Odd wiring in tube ampmschematics
On 12/10/18 6:22 AM, snipped-for-privacy@gmail.com wrote:
 > On Monday, 10 December 2018 11:42:17 UTC, Fox's Mercantile  wrote:
 >> Actually, the term "Split Phase" is accurate.
 >> The source is a center tapped 240 volt winding.
 >> -180 0 +180 degrees.
 >> Either side to center (neutral) is 120v, and across both sides (hot)
 >> is 240v.
 >> The usual problem is when people insist on calling it 2-phase due to

 >> It is not, the primary is single phase.
 >
 > 3 phase has an angle between each phase of 360/3 = 120 degrees.

Correct.

 > 2 phase has an angle between each phase of 360/2 = 180 degrees.
 > And that's what you have with the US domestic 120/240 system.

Absolutely NOT. That is center tapped single phase.
In the early days of electrical generation, there was 2-phase, but the
two phases were offset by 90 degrees.

--  
"I am a river to my people."
Jeff-1.0
We've slightly trimmed the long signature. Click to see the full one.
Re: Odd wiring in tube ampmschematics
On Monday, 10 December 2018 16:58:22 UTC, Fox's Mercantile  wrote:
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It's one of the 3 phase distribution system's phases, centre tapped, that i
s its source. That does not change the fact that it's 2 phase.

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I've read various times of 2 phase systems with 180 degree offset, but not  
seen 90 degrees.


NT

Re: Odd wiring in tube ampmschematics
OK - I am in an unique position here: I actually have worked with true 2-ph
ase power, developed in the 1920s before 3-phase was well-established, as a
 means to provide off-set to start motors. Also pretty much confined to Phi
ladelphia and Baltimore, being the two major cities in what became the PMJ  
Interconnect.  

From PECO Tariffs:



This is a four (4) wire system, and the neutral currents do not cancel even
 if the system is in balance. Hence the need for four (4) wires.  

I am surprised that so many went after the remark of audio and pacemakers.  
But here goes:

Pacemakers will accept all sorts of RF and other interference today - a vas
t improvement from the days when merely walking past a vintage microwave (i
n operation) would cause troubles.  

But the modern pacemaker/defibrillators do not like stray currents in the b
ody, as they may be taken as an event. If there is as much as a few volts d
ifference between the NEUTRAL and the GROUND, and an individual so-equipped
 steps into that difference, that could be enough to trip the defib-functio
n. Not (usually)fatal, but quite painful. Just ask the guy up on the 10th f
loor designing temporary artificial hearts - between restoring vintage Pors
ches. He will talk the paint off a board if given a chance - and I am suffi
ciently intrigued by what he does to give him those chances.  

And, of course, there are hum-loops caused by stray currents.  

Peter Wieck
Melrose Park, PA

Re: Odd wiring in tube ampmschematics
snipped-for-privacy@gmail.com says...
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Some do not understand that by definition and the way it is generated, 2  
phase power is 90 deg out of phase, not 180.

There for in the US the common feed of 240 and 120 volts can not be 2  
phase.  

https://en.wikipedia.org/wiki/Two-phase_electric_power



Re: Odd wiring in tube ampmschematics
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round in a household system, and the wiring is otherwise to-code (US NEC),  
something is wrong. "

Not true. If one side is loaded heavily that's what happens. One house, win
dow AC units, for example had 25 volts on the neutral because all the A/C u
nits were on one side of the line.  

In that house it was because the job wasn't planned right. It was code but  
a shit job. And nothing wrong.  

This can also happen in some older houses when the main neutral coming in i
s a smaller gauge than the hots. Even if not. If you put too much load on o
ne side it happens.  

Then if you blow the neutral fuse, which should not be there logically, it  
can throw 240 volts into everything on the lightly loaded side. Many houses
 around here are older. They did not anticipate all the load we have these  
days. I have had to change the lead in from the meter more than once, other
wise I would have had to put in like a 50 amp main or the job wouldn't be c
ode. I got them ready for the service upgrade to 100 amps. Actually 100 amp
s is not all that much these days. Not enough if you have a hot tub/jacuzzi
 or an electric furnace. If you have both, double it to 200 amps. (then the
y will probably put in a peak load meter to pick your pocket more effective
ly)

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