Alternating current & neutral wire

[starfury1]

Re: Alternating current & neutral wire

Hi Per, All

Don't worry mate you are not the only one,
I too did not understand it either when I first got into electronics and electrical.

It didn't dawn on me till I realized that I had to treat voltage and current as 2 separated items.

Then had the concept of "Voltage exists across" and "Current flows through"
Drummed into me.

this is why when you measure voltage the meter is parallel with what you are measuring.


When you measure current its in series, you have to break open the circuit and put the amp meter in as part of the circuit.

it is true what you say the circuit (at least the first part of the circuit) doesn't care with the Mains Alternating Current which way it is connected.

I guess where you maybe getting a bit lost on it is were this whole threaded started from.

So I will have another go at trying to put it in a way that unlocks it in your mind cause it really is simple.....

I guess the problem is we tend to look for the complexity in things not the simplicity.

you make the following comment;

I do not understand how there can be a difference really, it's AC after all, one big sinus wave moving between a couple hundred volt + and -

Please excuse the yelling , just trying to emphasis the point

one big sinus wave moving between a couple hundred volt + and - OF WHAT?

What is our point of reference?
What defines what is positive or negative
Positive with respect to WHAT?
Negative with respect to WHAT?

OK having posed those questions lets look at the terms for the wires

"Active" what does the word Active mean...
well basically doing something, so it is the DOING wire.

What does "Neutral" mean? passive, not one or the other, not committed.

We can at this point ignore the EARTH wire cause its only there for safety and as far as what we power has no real use.

OK bear again in mind I am going to lie for the sake of simplicity

lets see how the power stations generator works

We can create Electricity by using a magnet thats moving constantly
(we can also create a magnetic field with electricity)

suppose I have a shaft with a magnet on it, I then take 3 coils and place then close to the shaft in a circle.

(I have basically given you the 3 phase concept here but I am in no way going to go near that)

Now our coils will have 2 ends, so next lets take 1 of the ends of the 3 coils and whack then in the ground.

we are going to call those ends our return wire or "Neutral"

Lets now take the other end of the 3 coils and run each one to a separate house.

lets now take that wire to a power point in one of the houses and connect it to the ACTIVE marked point of the of the power point.

lets now take a wire form the Neutral marked point of the power point and whack that in the ground.

The end of the coil at the power station is in the ground.
The wire from the neutral of the power point is now in the ground.
The ground is now acting as the return wire.

Now here is were the confusion rains and it gets interesting

lets start spinning the shaft the magnet moves in a circle and starts to generate electricity in the coils.

THE coil now will have one end Positive with respect to the other end at a given point in time,
The other end of course would have to be Negative with respect to the Positive end.

if we look at the coil at a later stage in time, the ends will be opposite the Positive end will be Negative now and of course the negative end will be Positive

With respect to each other!

Confused! its all a matter of perspective really

So at one point our Neutral can be said to be positive with respect to our Active line and at the other max negative with respect to our Active line.

Since everything that sits on the ground is going to be at the same potential at any given point in time

which is either positive or negative with respect to the ACTIVE wire

why not just call in ground or zero volts and be done with it.

(so in a way Keyboradcowboy you are right)

Then we can say our active wire swings positive or negative of ground, which we are calling our return wire (since its common to all 3 coils)

If you think of the above,

we are the birds on the power line in one respect


OK Alternating Current

Current that flows in one direction then changes direction and flows in the opposite direction. It alternates

How do we do this easy change the polarity of the voltage

So when our Active line is a max positive current flows in one direction.
When it is at Negative the current reverses and flows back in the other direction

As stated above The technical reality of how our power grid works is much more complex then this

I am just trying to put it in its simplest terms to get the concept across

Well I guess I'll leave it now open for others comments
hope this makes sense and helps some understand what going on

few links

Alternating current

this on earthing power grid and more

how the power grid works
(Might have posted this one above)

Cheers

[shadow]

Re: Alternating current & neutral wire

Two great posts starfury1!
Your explanations are great!

I was going to try to explain this one, however when I got around to doing it I found it hard to type something out that would of made sense to someone who is possibly not familiar with AC theory at all.

The thing that seems to get people confused, especially with AC theory is like what starfury1 said about voltage and current. They are two very different things.

As far as I understand at the current time. Voltage is the potential energy between two points. Our reference point is usually ground/earth which we call zero volts. This sets up an electric field running from the positive point to our negative point i.e. from the positive terminal to the negative terminal in our homes.

Current on the other hand is the rate of flow of charge caused by this electric field (and this electric field was 'made' by the voltage between the positive and the negative terminal).

Things that I find helpful to remember are when talking around electronics are:
* Voltage is more than a number, it is the a difference of potential electrical energy between two points.
* Voltage sets up an electric field running from the positive point to the negative point.
* Current is the rate of flow of charge (electrons carry charge in wires)
* Current flows along electric fields.

Now if we look at alternating current. We know that voltage alternates between ±x volts (where x is a number in your particular country).

If we consider this very simple circuit.



At one stage in time, the voltage will be +x volts on one side (active terminal) and zero volts on the other side (neutral terminal). Current will flow from the from +x volts to the 0 volts.



At another stage in time, the voltage will be -x volts on one side with the other side being zero volts. Current will flow from the 0 volts to the -x volts.



This can be explained in the opposite order, if current flows in one direction. It must be flowing from a higher potential to a lower potential energy state (from +x volts to zero volts). If the current switches direction, current still flows from higher potential to lower potential energy (from zero volts to -x volts).

I find it important to realise that.

Hopefully I cleared up something and made it easier to understand some basic electrical properties which in turn should make it easier to understand AC theory.

[Per Hansson]

Re: Alternating current & neutral wire

The problem I have with it is that the neutral wire/return wire ground wire, whatever you want to call it because it's basically just the same never goes back to the think generating the currrent

We get 3 wires of high voltage, but there is no ground

I have problems understanding how the power can be transmitted at all when there is no return wire (i.e. like in DC where the return wire is the - which goes back into the battery cell)

This is my biggest gripe with AC, I understand voltage and current. Voltage isn't really dangerous. It is just a way to reduce the power losses at longer distances, however current is what kills me

I also understand the sinus wave (I think) it goes from + to - and the reference for that is simply the middle of the sinus wave, which I call ground but which could be positive I guess

However when I look at the power cables, thinking in the other end serveral hundred kilometers away is a nuclear power plant, which has a rod into the ground, and then just the phase wires coming out of it, no ground/neutral wires, that's where my brain tells me it should not work

Like we also buy power from Finland, and vice versa, so there is a cable through the sea... Carrying only the phases, in Finland the nuclear power plant is grounded, and then when that power cable comes to us here serveral gazzilion kilometers away and I run the phase into the ground I get current flowing through it, but why oh why...

I will look at your links tomorrow, maybe they will help, too late now...

[willawake]

Re: Alternating current & neutral wire

http://en.wikipedia.org/wiki/Three-phase_electric_power

[Tom41]

Re: Alternating current & neutral wire

There was a nice demonstration on one of the Open College "Power Base" TV programmes about AC and DC (late 1980s). I remember they showed a special setup where AC alternates very slowly - taking about 2 seconds to complete a full cycle. With the demonstration setup, they had a lightbulb connected to it... the lightbulb was only bright when the current was at the maximum peak either way. When the direction starts to change, the bulb dims and goes out, only to get brighter again when the other half of the cycle gets going.

With proper 50hz (or 60hz) AC, the bulb is dimming so quickly between the peaks that only the bright parts are apparent. Indeed, the filament will take a short while to go out when you remove power, unlike an LED.

It's a shame I didn't buy the special kit that went with the programme - I could have measured the voltage on the terminals when the AC was alternating slowly, and see if live/neutral made a difference!

Occasionally, when I touch a piece of equipment while touching something else that is grounded (such as a water pipe), I get a very sharp 'prick' feeling, as if I was touching the point of a pin. If I touch the same equipment while not grounding myself, it doesn't feel like anything at all. I'm sure the appliances all have the connectors wired correctly, and most are supposed to be double insulated.

[starfury1]

Re: Alternating current & neutral wire

Thanks shadow and yes It did actually take me a few hours to try and put those posts together in hopefully a way that would makes some sense.

A picture is worth a thousand words and unfortunately I didn't have any to hand which I could use.

I should add that its in no way the full story and i did leave out a few things as tom41 has pointed out time and amplitude of PD voltage

Thanks too for putting it in its more correct technical terms your post adds very good clarity to it Tom41's does too with the time and amplitude thing
Willawake thats an excellent link, thats the sort of stuff I was looking for but just didn't come a cross it in my searches.

As tom41 has pointed out that like bulb is gratually turning on and off
It is the fact its doing it so quickly and also our persistence of vision
(we hold the image for a small amount of time)
That creates the illusion its is on all the time
Tad more to it thought
(ditto for TV and motion)

Per I will have to read you posts a few time so it sinks in to my brain a bit.

As I said its really is very complex how its done but the idea is simple.

I should also add that in reality there is a wire (of sorts) that goes back to the generator but at points alone the way its tied to earth.

We also have transformers for stepping down the voltage to a consumer usable level and here is where we are starting to get into the complexity of the whole system

There is of course a reason for everything

One question that hasn't been posed Why AC why didn't we Just use DC?

The simple answer is it just don't work well at all.
Yes we have had DC power stations and a few that tried to make that a reality and also tried to suppress the AC method of distribution of power

We wouldn't have the power grid we have today if it wasn't for AC method of transmission

I stayed away from 3 Phase system for exactly that reason it really can get confusing and would have only added to confusion to my posts above.

But should have stated that I was only going to deal with a single phase.
Which is what most houses run off anyway..well here in OZ they do.

Have a look at that 2nd link it may clear up a bit more on why they used the ground with the neutral *
(* return line...of sorts, remember the changing direction of current flow)

I'll have a think about the 3 Phase and see if I can come up with a lie to tell you per

Since I don't work with electrical stuff I don't tend to think about 3 phase too much

Dont worry mate I really struggled with this when I first got into electronics

Most books described it all with maths and I hated maths at the time.
So had no real idea of what they were talking about.

Ok just food for thought

In Aust we use 240V AC rms
(think its being changed to 230 VAC now inline with other parts of the world)

When I look out my front door I have 4 wires on the poles
3 are Actives 1 is neutral

So 3 phases A B and C
Now if I measure the voltage across each phase (A or B or C) with respect to the Neutral it will be 240 V AC RMS Phase A,B,C ~Neutral 240VAC

If I now measure the Voltage Between any 2 of the phases
it will be 415 V AC RMS
A~B 415 VAC A~C 415 VAC B~C 415 VAC

I have between any 2 of the phases a voltage or Potential Difference of 415 volts

So one phase must be Positive with respect to the other phase
Which of course would be Negative
(I am looking at a moment in time here, remember its constantly changing and then reversing in reality)

If I now place a light bulb between the 2 phases would current Flow?
Would the light bulb light up

short answer YES

Why Cause I have a Potential Difference existing across the light bulb which will enable current to flow through the light bulb.
The light bulb is a conductor, just not a very good one.


No I think what you are getting at per is what the hell is happening at the other end to complete this circuit.


In my "crude imaginary lie of a model"
its simple

The 2 ends of the phase coils are tied together and whacked in the earth.
thereby completing the circuit

Our 2 coils don't care we have whacked then in the earth, just so long as they are electrically connected together
(we could even pretend that both phase coils are now just one big coil that provides 0 to a max of 415 V, the polarity of which will be constantly changing thereby changing the direction of current flow in our light bulb


So in effect depending on which phase wire is more positive at the time the other will act as the return wire

I think what you might really be seeking or asking is the technical reality of how its done and I guess this then puts you back at researching exactly how the grid is really put together.

I'll have a think on your post Per and get back to you

Cheers All

[Per Hansson]

Re: Alternating current & neutral wire

Hi and thnx for your long posts guys, especially starfury1!

Yea, I fully understand the distribution system in itself, why we use AC instead of DC (search for war of currents on wikipedia) And how and why power is transformed up and down

Where my problem lies is at the AC system itself. That is I do not see it as a complete circuit, whereas in DC you always see the complete circuit. You have the batteries positive and negative end and without the negative end there will be no current flow.

And I'd fathom a guess that if I connected a couple batteries so I got over 240v DC I would still not be able to do it the way AC does it; stick the negative side of the battery into the ground, then pull a conductor maybe 50 meters and at this side of the wire connect it to a lamp which I then take the negative pole from the earth

However if I now swapped out my 240v DC batteries with a AC generator it indeed would work

The power distribution system in Sweden is usually only 3 phases on the poles and that's it. This is because most of our powerlines are now insulated so we do not need a ground safety wire that the bare high voltage phase wires can ground to and blow a fuse somewhere incase something goes wrong with the physical installation...

What I have outside my hose here is an insulated 3 phase 10kV powerline, it goes to a 400v step down transformer. From here we have low voltage (400v AC) powerlines to the houses and at most houses you have all 3 phases available. The grounding/neutral is provided by the customer self. In our case a copper wire is dug down around our house...

[starfury1]

Re: Alternating current & neutral wire

Hi Per

I'll try and keep this brief as Its late here and I am tired...had a big day
And its not really an answer just a summary of what I think you are driving at in simple terms

Might help people understand what all my waffle was about above

I think to simplify what you are saying is that with the battery 2 wires and a light bulb.

You can see the circuit as a complete circle

(With that circle current only ever flows in one direction with DC.)
(ill add to this later)

Yes you are quite correct too with the AC
It must still be a complete Circle too.

But how that circle is completed with AC is what you cant see.

This is probably from the complexity added to it, in how its really done.

Throw the fact in, that we are using the earth as a wire and no wonder we get confused
(anyone interested, see link 2 above for some of the reasons as to why)


Per, You have with your 240v DC battery, 50 metre wire , earth return starting to hit on why we don't use DC transmission of power.

============================================

This is an analogy and by now means a perfect one

It does give partly an idea of how AC current works.

You have seen those things some people have at home or in the office.

you have a frame with 5 or 6 metal ball hanging on chains.

Now you lift one (ball 1) and let it drop....what happens is the last ball (ball 6) goes flying up into the air then stops and falls back, Belting back into ball 5 then ball 1 goes flying up and so on and so on.

Now the important thing to realize is balls 2345 didn't move.

But the energy of the first ball was transferred to ball six.

If you think of DC, you would have to have ball 1 end up were ball 6 is
(for a DC analogy this isn't a good one...but Ive got one up my sleeeve...yet to come)

I'll leave it there for the moment and I will seek out those wiki pages you mentioned above and have a read of them myself.

BTW that is rather interesting about your power system I will have to look into that.

Cheers Per , All

[gonzo0815]

Re: Alternating current & neutral wire

I would say, if you like an DC view of AC, lock into a basic shematic of an HIFI power amp with symetrical DC supply and consider the speakers coil as the AC consumer.....(and shure, forget abouth stereo ;-) ).
that`s how AC distribution realy is working IMHO.

[Per Hansson]

Re: Alternating current & neutral wire

starfury; I did lie a little about our circuits, there is a ground return wire that goes to the stepdown transformer from our houses... But that's just connected to it's frame...

From the high voltage power line there are still only 3 wires, i.e. 3 phases...

But I think my brain is starting to sense something, keep the info flowing, this has been a question I have tried to learn for years (and my father is an electrician btw :P)

And yes I know the reason we don't use DC is because of the tremendous loss of power in longer cables, it was only ever useful as a distribution medium in cities, and then it could only go a few blocks at most, here, I'll link the wikipedia I was talking about above:
http://en.wikipedia.org/wiki/War_of_Currents

So to absolutley explain my question, (I am seeing my question more clear now myself lol)
The problem I see is that we have the phase(s) coming from the power plant, but the ground/neutral wire never goes back to the power plant. It just goes into the ground...
In my mind not a complete circuit

[Per Hansson]

Re: Alternating current & neutral wire

These two links did help me (serveral more pages on the left menu of the first one)

http://www.allaboutcircuits.com/vol_2/chpt_1/1.html
http://www.triquartz.co.uk/ac.html

Especially the reason of why the voltage changes positive and negative in a sinus wave (because of the generator using a magnet that half of the rotations is not "infront" of a coil and therefore the voltage is zero)

I did not like their explanation further in that the averge AC voltage is really Zero volts, however after a while that too managed to sink in

I very much like making the analogy to something I can "see"
Not just math (as you guessed)

Hertz is the number of complete 360° revolutions per second the magnet in the generator makes. If we increase the RPM of the generator (spin the magnet faster) we increase the frequency
Voltage is simply a product of how many turns the coil in our generator has. If our voltage is 230v AC RMS then it's peak voltage is higher, and the peak to peak voltage is two times that.
Current is really how powerfull our generator is, i.e. how much water or steam is required to keep the generator at a constant RPM so our frequency stays at 50hz

This is atleast the way I currently see it, I can of course be wrong so don't include this as a reference in your degree in electricity

But I still miss the ground wire theory, I'm gonna take a phase wire tomorrow and hook it up to a lamp, then I'm going to "connect" the other side of the lamp to a steel rod in the ground

It will light up but I will be no more close to understanding exactly why it lights up

[starfury1]

Re: Alternating current & neutral wire

Yes Gonzo the old +/-DC of the Audio Amplifier and an AC signal plus the load.

It is a good one all round
I hadn't gotten to that and it is an important one to understand.

I was of two minds about using it, as I thought it might add a bit of confusion.

It also opens up a lot of concepts
what are you going to call "common, return, earth or for that matter negative" and Why and how is changing levels (voltage wise) of DC going to give us AC.

Also what for that matter is varying DC anyhow.

Per

Yes I myself don't know the fine details of how it does it with the power station either.

All I know is that some how, some way the circuit must be completed and the earth is used to do it.

So I assume the earth is a wire or being used at times as a wire for return or supply path for current.

I guess what can throw you is how the earth can act as a wire when its big...I mean really big! and looks nothing like a wire.

Perhaps this may help.
====================================================
Earth as conductor or resistor

Suppose I have two 1 metre square plates.

I stick them vertically in the ground 1 metre apart
(it doesn't matter this is just for an example)

I now attach it to a voltage source, lets pretend its your 240 V DC battery.

The ground or earth will have a finite value of opposition to current flow but it will also have the ability to conduct current as well.
(just not as good as a copper wire)

How well it does this is going to depend on the soil type and how moist it is.

Now I attach my battery to the 2 plates I will get an amount of current flow
it may be very small and useless for anything practical but it will flow

If I want to increase current flow and we are assuming here the grounds resistance is going to stay the same.

I would have to increase the the potential difference (we measure in Volts)

There is another way I could do this too.
By decreasing the resistance of the ground.

Water which is laden with minerals metals is a good conductor, which is mostly the type of water we have.

Pure H20 is a actually a good insulator and does not conduct electricity very well...well thats the story I am told anyway.

So imagine I take a watering can and wet the ground between the 2 plates in a 333.3 mm wide strip.
(dividing the metre wide into 3 strips basically)

This will reduce the soils resistance allowing more current to flow in the wet section.

Now does current still flow on both sides of the moist strip of soil?
yes but not as much.

Now suppose one of those outside strips (333.3 mm) I moisten just slightly.

I would have 3 strips of soil that the resistance of each would be different.

Or another way of looking at it is I have 3 values of resistors across my supply lines.

=======================================================

Digital TV is happening here in OZ ,and those trying to reduce interference by connecting the shield of coax to ground.
Some via the mains earth and I am not sure if thats strictly legal, others via an earth stake.

I have even read on one post.
Where the guy has his garden watering system, he has put the earth stake near there so its always in moist ground.

Per thanks for posting the links they are quite useful.... and suggest those that read this thread have a look too.

To you last post

Yeah I didn't get in to how the magnetic field and coils really work or the more technical correct why in which they work so thats a good support link.

The AC voltage thing equaling zero ...
think you got to look up Kirchoff's voltage and current laws.

I get confused with them too...its more a maths thing when its explained.
Algebra.

So the explanation's don't tend to work to well with me

Think basically what it gets at,
is what you start with gets used up around a circuit and at the end of the day what ever drops(voltage) or branches (current) you have
must equal what you started with
either current or voltage...but yeah don't quote me on it

So yeah I'll leave that alone , here as few links anyway

flash uses maths Here


brief outline Here

This one seems to spend a bit of time on it here

ON Hertz

Yeah perhaps they should have left that as Cycles Per Second
Yep 50 Hz is 50 Cycles Per Second.

Yes I didnt touch on that either in a clear way. RMS, peak or peak to peak

Simply put

If you have 1 Second of time and look at the DC voltage at any point in that second it will be the same...12 Volts 100 Volts whatever

But with AC voltage it is constantly changing over that 1 second in time.
As you have pointed out.

RMS is just the way we state its equivalent power to DC power over time.
voltage wise, cause with DC it would be constant over time.
Where as with AC its constantly changing over time.

So the AC RMS equals the DC voltage we would need for the same amount of power

ok thats brief and not the whole story

You have to be careful with the terms power Energy and work...they don't necessarily mean the same thing, I could have actually used the wrong term here.

Current is really how powerful our generator is,
i.e. how much water or steam is required to keep the generator at a constant RPM so our frequency stays at 50hz

Not quite sure on this but then again would probably have had to read in the context you did.

True though if you had a 1000w of electricity generator you would need to have a 1000W plus of mechanical energy/power To expend to create it'

sign off for now thing to do cheers

[Per Hansson]

Re: Alternating current & neutral wire

Some food for thought:

The neutral wire isn't special in any way. You can verify this by standing on the ground (ground as in earthglobe ) and touching the phase wire. You will get shocked... I.e. you became the neutral wire

The neutral wire is neutral vs the ground wire, you can verify this by touching it, you will not get shocked unless you provide a lower resistance to ground then what the wire does (obviously do not try this!!!)

Both the phase and the neutral wire carry the same current. I connected a load, it was 0.22aH no matter which way I plugged the contact into the wall...

The difference between the phase wire and the neutral wire is their potential difference, the neutral wire is connected to ground and should also be connected to the transformer creating the voltage/current so therefore it exists at 0v with respect to the phase wire which exists at 230v

The neutral wire is not really needed, you can swap it for another phase wire. You will now have 2 phases which will exsist at twice the one phase voltage in your country (460v AC RMS in most of europe)

You can create power which has no connection to the earth ground at all, look at normal gas powered generators and also DC>AC inverters (does this mean they are all 2 phase? I measured the phase>neutral voltage on a gas generator we have, ca 220v AC but from neutral to ground and phase to ground it was ca 110v AC... On a DC12v > AC 230v inverter I have the phase to neutral voltage was around 200v (poor battery powering it) and the neutral and phase to it's chassi voltage was around 60v and 80v each (it does not feature a ground connection at all)

Again I have not managed to explain why you get shocked when you touch the phase wire but not the neutral wire which goes back to the transformer. Since you are only touching one cable you are not completing the loop.
And the answer that the ground actually carries the full current (lets say 63aH) back to the transformer completing the loop does not work for me. The soil can not be that conductive (and in my case the step down transformer is over 200 meters away from my house)
Sure the ground and neutral wires are connected at more points to the ground inbetween but I still can't see the earth(globe) as a conductor of current

[starfury1]

Re: Alternating current & neutral wire

It seems that in my Quest to answer KBcowboy I may have put too far forward the Idea that the Earth is the return wire.

ITS NOT

I may have mention that at times the earth is used as part of the return path....I am not sure but something sticks in my mind that it is.
So I will have to look into it to obtain correct info on if it is or not.

My model as I stated was a LIE and only being use to try and Convey a few concepts on a simple level.

The Neutral is the return line that at times is connected to true Earth
for the reasons Explained in this this link.
WHY THREE PRONGS?

So I have some what lead Per up the Garden path... Doh!

Per has posed another question in this thread and its somewhat different but still related to the Neutral.

Since Per seems to like Circles (and so do I) and it makes sense to do it this way

This Diagram below would be some what more the Reality
But again its NOT Really how its done with the power grid


It comprises of three separated circuits (isolated) that are magnetically coupled together.


I have only shown it as a single Phase, each phase would be the same as far as using the Neutral is concerned.

THE BUT is,
if you start using the 3 Phases (with or without the Neutral)
it starts to get complex then, So I have stayed away from it
(again see the links in above posts for more info)

You will note

There is only one thing "common" to them all...the fact they have been connected to Earth we stand on


Now you can see that the Earth has the potential to be a return path but we are not using it as that

This is the Danger.... IT CAN BE!...used as a return wire....and when it is,
You are usually the resistive Load

THE DIAGRAM

Basically you have a spinning magnet generating Electricity in a coil
(actually coils.... see the links above through out this thread)

(Yes its is far from the truth the way I have drawn it.)

We then use a Step up transformer to set the Voltage Way up, lets say 330KV.

Why? cause at High Voltage you need a lot less current for the same amount of power (Volts X Amps) therefore you can make your cables a lot thinner.

Means a lot less weight
but there is always a trade off, you now have to space them way apart and up very high...

Now running 330KV into you house would not be a good idea...think of what I just said above and how well you would have to insulate everything....

So We put in another Transformer to step down the Voltage to a more user friendly and manageable level for consumers.

The Resistor is everything in your house.

Hope this makes a bit more sense.
-------------------------------------

Food for thought and a recap; below

Now if I disconnected all the lines on the Diagram from the lines marked Neutral and then connected them to the ones marked active, Electrically would there really be any difference to the concept on the Whole?

Strictly speaking yes (we are then going into other concepts and ideas)

Basically speaking as the concept goes here NO

Except I would now have to call may Actives lines Neutral and my Neutral Lines Active.

So to Recap what I said above

Remember, I said the ACTIVE is the DOING wire and will change polarity + or - with RESPECT to the NEUTRAL.
Which is connected to EARTH
Since everything sits on the Earth we all exist at the same potential at any point in Time

We at one point in time will be more positive or negative then the Active line.

Its somewhat a matter of perspective but we assign Zero Voltages to earth and the Active swings positive or negative of that Zero reference point

(The reality is some what different remember there are 2 coils per phase being used in the Generator, but putting it simply the above is correct. I just pretended in the example it was one coil)

There is a whole heap of info off the links on this page including some posted above

Here

Hope this helps

Cheers

[starfury1]

Re: Alternating current & neutral wire

Ok I knew this existed and just found the Wiki on it

SWER

Single Wire Earth Return

This might have been what I was thinking of when I was talking about the earth as a return wire.

If you read it you will see that mostly not done, except in Cases of $$$$

From the Wiki its seems to be a lot more common then I thought it was humm.

Seems also a lot more heavy duty system then my vague memory of it.

Still a proper conductor (wire) is the Preferred method so the above still stands with regard to the Neutral, Return wire I guess.

Anyway Per "Earth As A return wire".

Cheers

[starfury1]

Re: Alternating current & neutral wire

Since there has been some mention of domestic AC plugs/sockets in the threat just thought I would put this wiki in too

Domestic AC power plugs and sockets

you know the old saying... a picture worth a thousand words

[shadow]

Re: Alternating current & neutral wire

Since there has been some mention of domestic AC plugs/sockets in the threat just thought I would put this wiki in too

Domestic AC power plugs and sockets

you know the old saying... a picture worth a thousand words

Yer, I looked on that page before. I also found what I found a more interesting page:

http://en.wikipedia.org/wiki/List_of...nd_frequencies

I wanted to see that weird plug they have in Sweden with two ground 'prongs' which allows the plug to be inserted either way. The one Per Hansson was writing about towards the start of the thread.

[Per Hansson]

Re: Alternating current & neutral wire

starfury1; wow, thank you so much for that wiki page: http://en.wikipedia.org/wiki/Single_wire_earth_return

So infact it always is a looped system... I just could not believe that the earth could conduct electricity that well...

Live and learn

http://en.wikipedia.org/wiki/List_of...nd_frequencies

I wanted to see that weird plug they have in Sweden with two ground 'prongs' which allows the plug to be inserted either way. The one Per Hansson was writing about towards the start of the thread.

Erm yea, not that only Sweden has it, about 50% of the world uses that connector... (all of Europe except brittain but they don't count because they drive on the wrong side of the road)

[shadow]

Re: Alternating current & neutral wire

Erm yea, not that only Sweden has it, about 50% of the world uses that connector... (all of Europe except brittain but they don't count because they drive on the wrong side of the road)

Dang, I did not know that most of the world use that connector! Here in Australia we use a relatively exclusive plug too like the Brits!

Actually when I went on a holiday to Poland last year, they do not use that connector at all!
That is why I thought it was a weird plug.

In Poland they use the same European two pin connector like most of Europe. However they use this connector for their three pin connector.



Basically it is the French plug that the French use.

[starfury1]

Re: Alternating current & neutral wire

Hi All

Yeah it does Per but I really didn't think it was being used on such a grand scale in the case of SWER systems....it was a very long time ago I learned about the mains and it wasn't something I use every day so the info tends to be forgotten.

yes its a circle too...loop

Yep , now if you take my 3 earth resistors above and multiply it a zillion times you will get the idea.
You could look at it as zillion parallel/series resistors between 2 points.
Net result from parallel is going to be close to zero

Of course moist wet ground makes a much better low value resistor the say dry sand.
(sometimes it will act more like series resistors then parallel)

Remember its only a way to think about the ground

Anyway Per hope it helps you make a bit more sense of it all

Just remember what I have said above is not the exact total truth of how the mains power grid works just conceptually how it does it.

So guess you need to fill in the blanks of the real story mate

As to the mains plugs yeah they Really do use quite a variety.

Our plug does keep continuity with Active and Neutral so long as they are wired Right.
we don't have a fuse in them like the Brits.

Our Earth pin is a little longer (like the Brits)
so its the first to make contact and the last to break contact

I suppose it does make the system a bit safer, in that if an appliance has the Active switched(single pole) the circuit should be dead from the second side of the switch on (or really at Neutral potential)

Thats if as I said above,
some idiot hasn't wired the 3 pin plug or GPO the wrong way, remember the circuit doesn't care which way it is!

A lot of places in the past never seem to use the Earth as a safety wire and as far as a circuit is concerned you don't need it...its for protection of you when you try to become one with the light bulb.

Another Fellow Aussie Shadow

Cheers