Odd wiring in tube ampmschematics

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.

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.

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

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.

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.

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.

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.

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

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.

system. It can be 180 or -180 out of phase (Said for ease of understandin g). It can also be zero, but not likely,

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

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.

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.

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,

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.

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

NT

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

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.

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

Correct.

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.

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.

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

NT

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

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.