Re: Series Variacs

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

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

Why use the neutral? What would it accomplish? I have
240 volts with my two hot wires. I'm not currently
using a neutral on my 14.4 kV 25 kVA pig. If I were to
use the neutral, I might then worry about the two
variacs not being exactly at the same place at the
same time, since they aren't exactly the same size.
I'm not saying you're wrong, only that I don't see the
relevance in using a neutral.

You mentioned "many" problems, but only mentioned one.
I don't want to overlook anything.

And as for the NEC... we won't go there. I don't
remember seeing a section on hooking a pole mount
distribution transformer backwards, and wiring that in
series with either MOT's or a welder. The thing is a
giant code violation.

thanks
Adam

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Jeffrey Wiggins by way of Terry
> Fritz <twftesla-at-uswest-dot-net>"
> <jeffrey.wiggins-at-sympatico.ca>
> 
> Yikes!
> 
> I see many problems with your proposed arrangement.
> 
> Keeping in mind that I have only a limited
> understanding of this
> stuff...here's how I would do it:
> 
> Assuming your 240V is single phase, I would use the
> neutral anyway - the
> "bottom" of each variac
> would be connected here - and, depending on local
> electrical codes, would
> be tied to ground. The
> "top" of each would be connected to each leg of the
> 240V supply. You would
> then have to gang the two
> such that the wipers each arrived at the "0V" and
> "120V" positions at the
> same time. This way, the
> output between the wipers would vary from 0V to 240V
> as you require.
> 
> Does this make sense, or am I completely "out of
> it"?
> 
> My C$0.02 worth (about US$0.013).
> 
> 
> 
> Tesla list wrote:
> 
> > Original poster: "Yurtle Turtle by way of Terry
> Fritz
> <twftesla-at-uswest-dot-net>" <yurtle_t-at-yahoo-dot-com>
> >
> > I have two 120 volt variacs. One is 5,000 watts
> and
> > the other 5,500 watts (for incandescant loads).
> Can I
> > simply series them and run at 240 volts, using the
> two
> > wipers as the outputs? I don't currently use a
> > neutral, so I don't invision connecting anything
> to
> > the "center tap". I don't see how this arrangement
> > would need chokes. The variacs can be more or less
> > ganged, so I should be able to keep them fairly
> equal.
> >
> > thanks
> > Adam
> >
> > --------------
> >  ^            )
> >  |            )
> >  |            )
> >  |            )<-------
> >  |            )        ^
> >  |            )        |
> >  |            )        |
> > 240 v.     ---      0-240 v.
> >  |            )        |
> >  |            )        |
> >  |            )        v
> >  |            )<-------
> >  |            )
> >  |            )
> >  v            )
> > --------------
> >
> > =====
> > Adam Minchey
> > yurtle_t-at-yahoo-dot-com
> > www.geocities-dot-com/yurtle_t/index.htm
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Yahoo! Auctions - Buy the things you want at great
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> 
> 
> 


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

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