[conspire] Fade and open Neutrals

[Texx]

Two phase turns up in older motor systems.
I think its pretty much extince.  Its pretty oddball stuff, often locally
generated or supplied by rotary converter.
In 2 phase, second lead is off from first lead by 90 degrees, then the
other 2 leads are the opposite of the first 2.

In single phase, one of the hots is the RETURN of the other.
Adding the neutral tap in the middle of the transformer does not change the
number of phases.

These things need to be known and understood to pass either an AC theory
class or an electricians exam.

Im sure you hear it both ways, but there are a lot of fallacies out there.
Example falacy: "If you use a color other than red on the plus, you will
blow up the battery"
Truth: You can use whichever color you wish as long as you end up with plus
to plus and minus to minus.

Failing my AC theory class, really hurt me scholastically, and I worked
hard to get it right afterwards.

Slightly off topic points:

Often, automotive alternators are 6 phase.

Getting into power plant generating is a tad out of topic, so I didnt wade
in there.
As a toddler, I was running around in power plants under construction.
(Now you know why I turned out funny)

Im wrestling with spelling, and I vs i, punctuation gets attention but I
don't catch everything.


On Fri, Apr 17, 2020 at 2:27 AM Michael Paoli <
Michael.Paoli at cal.berkeley.edu> wrote:

> > From: Texx <texxgadget at gmail.com>
> > Subject: [conspire] Fade and open Neutrals
> > Date: Tue, 14 Apr 2020 20:12:43 -0700
>
> > Primary feeds a step down transformer, so we take 4000 and step it down
> to
> > 240 volt wire to wire.
> >
> > This secondary winding has a tap at the centre point.
> > At the pole this "neutral" tap is bonded to earth.
> > This is why you have 3 wires coming to your house.
> >
> > Im talking US single phase here.
> >
> > By the time the service line gets to your fuse box, the Neutral is
> probably
> > about 15 volts above earth.
>
> That can vary.  There are also different practices, including older,
> and more modern, regarding bonding neutral to ground.  Notably when
> it must/should/shouldn't/mustn't be done, and where.
> I'll provide one teensy hint of some relevance: GFCI
>
> > The 2 hot wires are 180 of of phase from each other.  They are opposites.
> > When the first hot is at maximum + the other is at maximum - and vice
> versa.
> > Do NOT call these 2 hots "phases"!  This is NOT TRUE!
>
> Hmmm, I dunno, I've often heard it called 2-phase.  Now, whether one
> calls it 1-phase, or 2-phase, I don't think it really makes a practical
> difference.  1-phase, simple enough, 2-phase, when you go from 1 to 2, the
> 2nd "phase" is 180 degrees out-of-phase.  So, calling it 1 phase or 2
> is sort'a a matter of perspective, and doesn't really make too
> much difference.
> 3-phase and up, continues logical extension thereof.
> So, N-phase, would be 360/N degree phase difference between legs.  N,
> of course, being a positive integer.  So, 1, 2, 3, 4, 6, all kind'a common.
> Most others that exist are typically some integral multiplier of those,
> but large numbers of phases are pretty rare ... don't think there's any
> 3-digit phases in practical common use anywhere - at least that I'm aware
> of.  But sometimes huge generators can have large numbers of phases.
> Often some large multiple of 3 - and those will be handed out to
> distribution lines as sets of 3-phase each ... so something like a
> 12-phase multi-megawatt generator might service 4 large 3-phase circuits.
>
>
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-- 

R "Texx" Woodworth
Sysadmin, E-Postmaster, IT Molewhacker
"Face down, 9 edge 1st, roadkill on the information superdata highway..."
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