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Re: 240 vac variac observation
Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>
In house wiring in the US there should NEVER be 240 volts AC to common. I
think you are using the two hot wires to feed your variac. Your drawing is
not correct.
If you do have 240 AC to common/neutral then you have
a dangerous condition and it should be corrected immediately. I have been a
licensed electrician and electrical engineer for over 40 years, what are
your credenials?
allan
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, February 07, 2002 9:00 PM
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>
>
> 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
> > > > >
> > > > >
> > __________________________________________________
> > > > > Do You Yahoo!?
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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
>
> _
>
>