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Zyp

wrote:
On Aug 17, 8:04 pm, George wrote:
Tony wrote:
Chris we are not going any way so I am not going to comment
however? there is no such thing in AC circuit as positive
and negative the on three phase system or single phase,
the phases are out of phase by 90 degree
that is it! no positive or negative
just about 6-7 months ago I had job replacing 25 hp Refrigeration
compressor that runs on 480 three phase and guess what
one phase was neutral, amazing isn't and you telling me
neutral is not carrying current I afraid you will need eat few more
Winnies by have nice day Tony

He is simply trying to give you a simplified analogy.

The legs on a three phase system are 120 degrees out of phase with
each other. On a single phase system the legs are 180 degrees out
of phase with each other.

I can't believe you guys have taken this crazy discussion with Tony to
3 phases. He obviously doesn't even understand 2 phases. When he
said:

"It is been so long since I stody the basics of Kirechhoffs Law,
That I would not atempt to go there
Tony "

it became obvious he's totally unqualified to be giving advice or
opinions on current flowing in a shared neutral. Kirchoff's Law is
quite simple and elementary: The sum of all currents at any node must
be zero. Which is to say, current can't pile up, it has to go
somewhere. In the case of a 240V shared neutral settup, that means
whatever current goes up one hot must either go back on the other hot,
which is out of phase or back via the neutral.

And to go back to the example Chris gave earlier, on a shared neutral,
if you put a 100W light bulb from one hot to neutral and another 100W
light bulb on the other hot to neutral, you will have zero amps
flowing in the neutral because the load is balanced. The current
flows from one hot, through the first bulb, through the second and
back via the other hot.

Now connect another light bulb from one hot to neutral, then you will
have current flow in the neutral.

Very basic.

Thank you!

--
Zyp