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