AC circuitry: basics of energy flowing and returning to its initial source (origin)

[DjMadness]

Hellos

In AC circuits, electrons flow from phase (live) and must return to neutral through a load (assuming single phase) just like the way in DC circuits where energy flows from + and return to - (supply terminal) hence "completing" the circuit and doing a significant job i.e glowing a lamp, rotating a motor....

My question is: suppose you have a single phase AC supply L-N (that is divided from the initial 3p supply + N from the transformer) call this the grid supply. On the other hand, assume you have a generator (3p, xkVA, diesel...) if you branch a 1p load terminals one to the L from grid, other from N of the generator, the load functions. There is no complete circuit (path) between L and N that are in fact got from 2 different supplies. How is this possible?

Thanks in advance
Dj

 

[Marvo]

There is always a circuit if there's current (electrons) flowing.

The neutral of the grid supply and the neutral of the generator are both connected to earth somewhere.

 

[DjMadness]

There is always a circuit if there's current (electrons) flowing.

The neutral of the grid supply and the neutral of the generator are both connected to earth somewhere.

Hi
The neutral of grid is created by the common point of secondary Y of the MV to LV delta-Wye transformer.

The neutral of the generator is private for its own.

There is no earth link between these two. How can you say that there is always a merge between neutral and earth?

 

[Mike177]

Because as Marvo said, the 'neutral' is the return path. Think of the star point in a wye transformer, it runs to ground.
The correct term is, I believe, referenced to the general mass of earth. In single wire earth return systems, there is no neutral, yet the system works over hundreds of miles. Or PME, the neutral and earth are linked frequently on the way back to the substation.

 

[dmxtothemax]

The ground or earth if you like is effectilly neutral,
Neutral and ground are bonded together in dozons of locations
around any electrical instalation, so if it can get to ground, it will also get back to neutral.

 

[snowhead]

The neutral of the generator is private for its own.

There is no earth link between these two.

If the Neutrals are not connected together or both are not connected to earth, then there won't be any energy flow from L on the Grid to N on the Generator.

If there is energy flow then they both are either connected or both are earthed somewhere.

It would be the same as using + from one battery and - from another without any other connection between the 2 batteries.