Re: 240 vac variac observation

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

Original poster: "Yurtle Turtle by way of Terry Fritz <twftesla-at-qwest-dot-net>" <yurtle_t-at-yahoo-dot-com>

The use of CAPS is for emphasis, I'm not SCREAMING!

You're missing my point. With two 120 volt variacs
back to back, there are TWO brushes. My 240 volt one
has ONE.

I never stated anything about PHASING, I simply stated
that varying my 240 volt variac results in an output
of 0 to 240 volts, RELATIVE TO THE COMMON. And in
residential 240 volts usage, WITH MY VARIAC, the
common is one leg (excuse me for using the word
phase). This results in one output leg at a different
potential RELATIVE TO THE NEUTRAL than the other. You
don't need a scope to prove this, just look at my ugly
ascii diagram below and noodle it out. At any setting,
I get 120 volts differential between the common and
the ground. This MUST BE, if you look at how the thing
is wired up. I also confirmed this my my DMM. How else
could this thing be wired? Of course, this doesn't
matter when I use my pig, as I don't use the house
neutral/ground connection.

 --------)
         )
         )<------  0 - 240 vac
         )
 240 vac )
         )
         )
         )
 --------)--------  common

 ------------------ neutral/ground


Adam


--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Allanh by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>
> 
> You can run two varics back to back and they will
> work
> fine but the fact remains that on standard house
> wiring the
> two phases are out of phase, 120 on leg and 120 on
> the other ( reference to
> gnd. and neutral) and 240 across the
> two phases. They are 180 degrees out of phase. If
> you have an oscilloscope,
> put one lead on one phase and the
> other lead on the second phase, you will see two sin
> waves 180 degrees out
> of phase. I live in Georgia also,
> where in Ga. do you live?
> 
> allan
> 
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Thursday, February 07, 2002 11:06 AM
> Subject: Re: 240 vac variac observation
> 
> 
> > Original poster: "Yurtle Turtle by way of Terry
> Fritz
> <twftesla-at-qwest-dot-net>" <yurtle_t-at-yahoo-dot-com>
> >
> > Not with my variac. As I stated, here in Georgia,
> > neutral = ground. To vary both phases would
> require 2
> > brushes. Mine is exactly as stated. I did however,
> run
> > two 120 volt variacs back to back, which did as
> you
> > stated.
> >
> > --- Tesla list <tesla-at-pupman-dot-com> 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 nutral. That means 120
> > > volts AC on each side of nutral 180 degrees out
> of
> > > phase.
> > >
> > > allan
> > >
> > >
> > > ----- 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
> > > >
> > > >
> > > >
> > > > 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.
> > > >
> > > > Adam
> > > >
> > > > =====
> > > > Adam Minchey
> > > > yurtle_t-at-yahoo-dot-com
> > > > http://www.geocities-dot-com/yurtle_t/index.htm
> > > >
> > > >
> __________________________________________________
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> > > >
> > > >
> > > >
> > >
> > >
> > >
> >
> >
> > =====
> > Adam Minchey
> > yurtle_t-at-yahoo-dot-com
> > http://www.geocities-dot-com/yurtle_t/index.htm
> >
> > _
> >
> >
> 
> 
> 


=====
Adam Minchey
yurtle_t-at-yahoo-dot-com
http://www.geocities-dot-com/yurtle_t/index.htm

_