Re: 240 vac variac observation

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

Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>

No, out of phase means that 240 will be seen from hot to
hot. If the two phases were "in phase" the difference between the two hots
would be zero. It would be like putting two NSTs in parrallel, twice the
current but the
same voltage.

allan


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, February 06, 2002 8:15 PM
Subject: Re: 240 vac variac observation


> Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<davep-at-quik-dot-com>
>
> Tesla list wrote:
> >
> > Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <allanh-at-starband-dot-net>
> >
> > If you are speaking of normal house wiring, you drawing
> > of the 240AC is wrong. A 240 variac varies each phase of the line
> > voltage in reference to neutral. That means 120
> > volts AC on each side of nutral 180 degrees out of phase.
>
> In phase.
> If out of phase, they would sum to zero across the
> two hots....
>
> Hint:  Measure phasing differentially....
>
> best
> dwp
> =====================================================================
> > ----- Original Message -----
> > From: "Tesla list" <tesla-at-pupman-dot-com>
> > To: <tesla-at-pupman-dot-com>
> > Sent: Wednesday, February 06, 2002 6:43 AM
> > Subject: 240 vac variac observation
> >
> > > Original poster: "Yurtle Turtle by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <yurtle_t-at-yahoo-dot-com>
> > >
> > > I'm probably stating the obvious to most of you guys,
> > > but this is something I recently discovered, regarding
> > > > 120 volt variacs.
> > >
> > > In my neck of the woods, neutral = ground.
> > >
> > > With a 120 volt variac, we are varying the output
> > > potential relative to neutral. No problem. See below:
> > >
> > > --------)
> > >         )
> > >         )<------  0 - 120 vac
> > >         )
> > > 120 vac )
> > >         )
> > >         )
> > >         )
> > > --------)--------  common
> > >
> > > -----------------  ground
> > >
> > >
> > >
> > > In a 240 volt variac setup, we are varying the
> > > potential relative to one phase, from 0 to 240 volts.
> > > This results in an unsymmetric 0 - 240 volts relative
> > > to neutral/ground. See below
> > >
> > >
> > > --------)
> > >         )
> > >         )<------  0 - 240 vac
> > >         )
> > > 240 vac )
> > >         )
> > >         )
> > >         )
> > > --------)--------  common
> > >
> > > ------------------ ground
> > >
> > > For example, I have a 34 kV DC PSU which wants 208
> > > vac. If I feed it from my big variac, one leg will be
> > > at a higher potential relative to neutral/ground, than
> > > the other.
> > >
> > > Perhaps that's not a problem, but it might be for
> > > some.
>
>
>