Re: Repost RE: Explain 3 Phase

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Alex Crow by way of Terry Fritz <twftesla-at-uswest-dot-net>" <alexcrow-at-blueyonder.co.uk>

Yes, it is 180 degrees out. Any *electronic* engineer will tell you that the 
two lines are 180 out of phase. The ground reference has *no effect* and can 
be ignored! The waves are a mathematical function of time, but the "time" 
axis actually represents the "angle" input to the trigonometric functions.

Eg the top wave could be represented as

V1=sin(t)

and the bottom as

V2=sin(t+180)

if, of course, you are using degrees to calculate. Most electronic texts use 
radians by default. The phase angle is unaffected by any static rail between 
the lines. Of course, I know where you are coming from, ie measuring V1 from 
Ground to the top live, then V2 from the bottom live up to ground. Yes, then 
the signals will appear to be in phase, but it's not something you'll find 
most guys doing here. We always talk in degrees of phase shift between 
lines/signals.

Alex Crow


On Wednesday 02 May 2001 04:31, Tesla list wrote:
> Original poster: "davep by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <davep-at-quik-dot-com>
>
> >      |---|   |---|   |---|                         ----------------------
> >
> > 0    |   |   |   |   |   |
> >   ---|   |---|   |---|   |---                   0
> >
> >                                         OR
> >   ---|   |---|   |---|   |---
> > 0    |   |   |   |   |   |
> >
> >      |---|   |---|   |---|                      0
> >
> >                                                    ----------------------
>
> 	errrrr
> 	That's 180 out.
> 	That's what a (two channel) scope will show
> 	REFERENCE THE GROUND/NEUTRAL.
> 	The 220 load is connected from line to line and sees the
> 	two (in phase) voltages adding.
>
> 	On the right is NOT what will be seen.  Anywhere.
> 	Add the wave forms, yields:
> 				0--------------------
> 	Adding the two voltages in the common home system yields
> 	2220, rather than zero...
>
> 	There is a hidden inversion in viewing the waveforms
> 	REFERENCE THE assigned ground.
>
> One has:
> >      |---|   |---|   |---|
> >
> > 0    |   |   |   |   |   |
> >   ---|   |---|   |---|   |---
> >
> >      |---|   |---|   |---|
> >
> > 0    |   |   |   |   |   |
> >   ---|   |---|   |---|   |---
>
> These add to:
> >      |---|   |---|   |---|
> >
> > 0    |   |   |   |   |---|
> >
> >   ---|   |---|   |---|   |---
>
> 	So the two 110s add to 240....
> 	Which, we know, is what happens.
>
> 	ALL that is necessary is to recall that the ground being in the
> 	center leads to an 'invisible' inversion in one leg.
>
> 	(I have watched an entire computer companies electronic
> 	hobbiest group get Just This Snarled on this issue.
>
> 	Just keep reminding:
> 		Adding out of phase yields zero.
> 		Adding in phase yields double.
> 		House wiring yields double.)
>
> 	(Historical Note:
> 	Edison (yeah, him....) cooked up this system, for DC.
> 	Necessary because its hard to run voltages up and down in
> 	a DC system....)
> --