Current flow in neutral but no voltage ?

[Rob678]

Having a challenge understanding the concept behind why when you measure across line and neutral (live circuit) using voltage indicators we have voltage reading of 230V single phase. If there is current flow in the neutral why is it termed as 0V ?
On that basis, second question - If I tested across Neutral and Earth, there is current flow down the neutral back to the transformer, why would the tester show 0V ?

 

[Rob678]

Yes the voltage (tension) is only on the live side as it were. The pulling and pushing distance moved was the current. Both ends of the rope move the same. The current in L and N are the same.

yes

Yes. The ground is a conductor, so your imaginary cable is 'real', but with some resistance (sorry thats probably a complication!)

I think I follow, yes. I find it easier to think in terms of current flow - just call it current - rather than worrying about electrons pushing or pulling.

Yes

Thankyou very much for all the help, I’m sure there’s lots more to learn but I do feel like I understand the answer to the question I initially asked.
So that all being said the phase conductor comes from the transformer to the installation and the neutral goes back to the transformer to the centre.
Back at the transformer on the opposite side of the windings we have the side of the transformer which goes back to the generator. (Let’s keep it simple and say there is only generator - transformer - installation). On the generator side of the transformer or back at the generator. What is the determining factor as to why it’s the tips of the star connection where our phase wire connects that carry the voltage ?
I would have expected back at an AC generator for a single phase to be connected in the generator at 180 degrees ?
What I’m asking is back at the generator which side is our voltage being produced on to then attach to the phase cables ?

I feel the answer is because of the neutral introduction, or to do with the way delta and star are connected ?

 

[Rob678]

Just had a look at some animations of a star and delta connection. Think I was getting slightly confused.
Taking mention back to previous early comments. All the phases work together because they are balanced as they leave the generator and then I’m guessing on one side of the transformer we have a delta connection and on the other side is a star connection. In this portion is where we get our phase conductor at the top which gives us the voltage transfer ?

 

[Avo Mk8]

Just had a look at some animations of a star and delta connection. Think I was getting slightly confused.
Taking mention back to previous early comments. All the phases work together because they are balanced as they leave the generator and then I’m guessing on one side of the transformer we have a delta connection and on the other side is a star connection.

Firstly, power distribution is not my thing, I'm not the best person to advise.
Conceptually you summary is fine. All phases are typically held at about the same voltage, via an earthing transformer or similar at the generator. And as you say, the generator can provide a balanced feed to a delta to star transformer to step down the voltage and provide the star tap.

In this portion is where we get our phase conductor at the top which gives us the voltage.
But it’s we get from one side to the other Im not sure about. Is that correct ?

Not sure what your asking here, but at the star outputs of the transformer you have the three live phases (don't touch!), and their star neutral point that is connected to ground (can touch!). So you could feed three households, one from each phase, and a neutral return to each. And in the unlikely event all three households are using exactly the same amount of electricity, eg the same current, (a balanced load), that current will be flowing in the neutral wires back to the transformer, and where the neutrals all connect together, their currents sum to zero. So for balanced household loads, the star neutral point of the transformer wouldn't carry any current. Mind blown. Of course that's an idealised situation.

 

[Rob678]

Firstly, power distribution is not my thing, I'm not the best person to advise.
Conceptually you summary is fine. All phases are typically held at about the same voltage, via an earthing transformer or similar at the generator. And as you say, the generator can provide a balanced feed to a delta to star transformer to step down the voltage and provide the star tap.

Not sure what your asking here, but at the star outputs of the transformer you have the three live phases (don't touch!), and their star neutral point that is connected to ground (can touch!). So you could feed three households, one from each phase, and a neutral return to each. And in the unlikely event all three households are using exactly the same amount of electricity, eg the same current, (a balanced load), that current will be flowing in the neutral wires back to the transformer, and where the neutrals all connect together, their currents sum to zero. So for balanced household loads, the star neutral point of the transformer wouldn't carry any current. Mind blown. Of course that's an idealised situation.

Thankyou very much for your help truly. Dis regard that last section I was looking at a picture of delta and star connection diagrams and taking them far to literal. I drew a Y inside an equilateral triangle to look how it would work and did a bit more reading to see how the coils actually wind around next to each other to create the contacts.

I feel like I’m there or there abouts.
Lastly I gather at a generator the ends of the cables are connected together in a Delta fashion. Then if we follow these three cables all the way over the plyons through the system eventually we get to a transformer which steps it down. We have a star or Delta connection one side and star on the other. Then from the star supply side, our phases then feed say a road of houses, and each of these houses taps onto the neutral to allow for single phase ?
If this is correct Thankyou very much for the help over the weekend. I’ve Definatley got a lot more knowledge than I started with on Friday.

 

[Avo Mk8]

Then from the star supply side, our phases then feed say a road of houses, and each of these houses taps onto the neutral to allow for single phase ?

Absolutely. All get the neutral and a phase. Blocks of flats and commercial buildings tend to get all 3-phases (and the neutral obviously), phases shared out within the building to balance the load where practicable. My previous house actually had a 3-phase supply to the fuse head, but just a single phase was connected to the meter.

Best wishes for a future in Electrics. Keep the faith!

 

[Rob678]

Absolutely. All get the neutral and a phase. Blocks of flats and commercial buildings tend to get all 3-phases (and the neutral obviously), phases shared out within the building to balance the load where practicable. My previous house actually had a 3-phase supply to the fuse head, but just a single phase was connected to the meter.

Best wishes for a future in Electrics. Keep the faith!

Thanks again, I’m sure I’ll be back with many more questions