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Re: Ganging Variacs (fwd)
---------- Forwarded message ----------
Date: Sat, 18 Aug 2007 15:46:25 -0700
From: Frank <fxrays@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Ganging Variacs (fwd)
Couple of comments and questions.
First, you cannot parallel Variacs, you would be driving one or the
other as they would not be identical.
I have to assume ganging as used here would be a number of Variacs on
a single shaft and each one controlling a single phase of a multiphase system.
You can use Variacs as a voltage control or as a series reactance or
a couple as one of each.
Important to note, a Variac will operate at its max output in the
center of its span just fine, if you try and use it at max current at
either end of the adjustment, you will burn the windings out.
As mentioned on previous posts, a used Variac needs to be stripped
and cleaned before use and even one in your system needs periodic
cleaning to prevent hot spots or arcs.
Typically MOT's or pigs need some sort of ballasting to limit the
current, NST's do not.
I have 1937 Tesla coil article that has an easy to made ballast choke
used in conjunction with a 5 KV pig if anyone is interested. It is a
~ 2.5 MB file.
Frank
At 12:18 PM 8/17/2007 -0600, you wrote:
>---------- Forwarded message ----------
>Date: Fri, 17 Aug 2007 11:43:21 -0400
>From: timjroche@xxxxxxx
>To: tesla@xxxxxxxxxx
>Subject: Re: Ganging Variacs (fwd)
>
>
>
>
>Adam, Terry, Bert, et al.,
>
>?firstly Adam, I agree 1000%!! I, as do many I am sure, get my parts
>surplus, I NEVER apply any power or voltage to a variac without what I
>like to call a "50,000 mile tune up". I break it completely down as far as
>I can, to the point of NOS status when I am done cleaning it.
>
>
>????? Thusly, I understand y'alls points on using a different ballasting
>option, and in many aspects of this hobby, passion, etc... to each there
>own. I take great pride in being able to say that I have had and continue
>to have the opportunity to learn first hand from the school that is
>undisputedly the finest TC builders since Tesla himself. I am speaking of
>coarse of Mr. William Wysock, Mr. Lowell Beezley, & Mr. Charles Strozier.
>With that said, I find it very interesting that?many of you suggest, and
>in turn you yourselves follow, an option that ties your hands behind your
>backs; speaking of a non-immediate adjustable current control or phase
>shifting device. it is without question an issue of most importance -
>availability. to many, as in spun Al vs. homemade toploads, current
>control variacs are simply not an option due to cost or availability, with
>that said, using variacs in this manner not only shows that the 120BPS (@
>60 cps) concept and only concerning ones self with the voltage waveform is
>greatly over emphasized?but that it is not consistant with the nature of
>how the tank circuit and thusly the entire system actually works.? ?????
>
>????????Please understand that I am in no way personally attacking anyone
>or am I saying that it will not work. That would be very close-minded and
>down right wrong. However, there are many concepts and notions that
>perpetuate for reasons beyond the scope of this discussion that may seem
>logical, but simply aren't rooted in good, accurate science. I was?told by
>the Dean, at that time, of the Dept. of Engineering at U of Illinois to
>NEVER forget one thing about "electricity"; Electricity DOES NOT follow
>the rules of logic, it follows the LAWS of Physics.
>
>
>??????? I started this string by asking the simple question - is it
>necessary to use a balancing choke on ganged variacs that are wired as
>current limiting devices and not voltage control?
>
>
>-----Original Message-----
>From: Tesla list <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Sent: Fri, 17 Aug 2007 5:29 am
>Subject: Re: Ganging Variacs (fwd)
>
>
>
>
>
>---------- Forwarded message ----------
>Date: Fri, 17 Aug 2007 03:16:54 -0700 (PDT)
>From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: Ganging Variacs (fwd)
>
>If you get an old one, be sure and clean it out before
>using. I think dust bunnies in mine helped contribute
>to several flashovers between windings. I think
>coiling is harder on a welder than welding; even with
>filters, and a TVSS.
>
>Adam
>
>--- Tesla list <tesla@xxxxxxxxxx> wrote:
>
> >
> > ---------- Forwarded message ----------
> > Date: Thu, 16 Aug 2007 20:53:22 -0600 (MDT)
> > From: Chip Atkinson <chip@xxxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: Re: Ganging Variacs (fwd)
> >
> > Man, I have to agree with Dave. You can get a
> > decent arc welder on ebay.
> > I use a lincoln AC-225. I have it wired in series
> > and put a plug on the
> > outside of the power cabinet. On top of it all I
> > have an arc welder!
> >
> > My feeling is that why wreck either a good variac or
> > a good welder when
> > you can set things up so you can preserve both?
> >
> > The arc welders on ebay are around $100-200 and
> > shipping seems to max out
> > at $55.99.
> >
> > Looking on ebay, variacs are at least that.
> >
> > Chip
> >
> > On Thu, 16 Aug 2007, Tesla list wrote:
> >
> > >
> > > ---------- Forwarded message ----------
> > > Date: Fri, 17 Aug 2007 02:42:26 +0000
> > > From: david baehr <dfb25@xxxxxxxxxxx>
> > > To: tesla@xxxxxxxxxx
> > > Subject: Re: Ganging Variacs (fwd)
> > >
> > >
> > >
> > >
> > > Why waste a nice Variac ?,...get a cheap variable
> > shunt arc welder and
> > > be done with it,
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
>________________________________________________________________________________
> > >
> > > From: "Tesla list" <tesla@xxxxxxxxxx>
> > > To: tesla@xxxxxxxxxx
> > > Subject: Re: Ganging Variacs (fwd)
> > > Date: Thu, 16 Aug 2007 20:23:45 -0600 (MDT)
> > > >
> > > >---------- Forwarded message ----------
> > > >Date: Thu, 16 Aug 2007 19:08:58 -0700
> > > >From: Barton B. Anderson
> > <bartb@xxxxxxxxxxxxxxxx>
> > > >To: Tesla list <tesla@xxxxxxxxxx>
> > > >Subject: Re: Ganging Variacs (fwd)
> > > >
> > > >Hi Terry, Tim,
> > > >
> > > >I did the same with my variac. I split the
> > core to prevent
> > > saturation.
> > > >It's been a life saver for me since I only
> > use a single
> > > variac with my
> > > >pig. But, if I had a large enough variac or
> > two, I wouldn't
> > > have done it
> > > >(as it does ruin the variac for any other
> > purpose). But if
> > > it's solely a
> > > >current limiting variac, cutting the core
> > will help prevent
> > > saturation
> > > >issues, although I have smoked the brushes
> > on this variac
> > > from too much
> > > >current. Even though saturation is
> > prevented, current still
> > > flows and
> > > >the components that make up the variac can
> > still be damaged
> > > if high enough.
> > > >
> > > >BTW, remove the brushes at least once a
> > year and inspect
> > > them. Can
> > > >prevent a bad situation. The smoked brushes
> > occurred at my
> > > 2005 4th of
> > > >July party. Funny, I just turned the
> > current down and the
> > > smoke went
> > > >away. The coil kept on Rockin! The next
> > weekend I did the
> > > optopsy and
> > > >found I was running on about 1/3 brush
> > surface. I learned
> > > from that
> > > >experience to inspect brushes and replace
> > when worn.
> > > >
> > > >Take care,
> > > >Bart
> > > >
> > > >Tesla list wrote:
> > > >
> > > > >---------- Forwarded message ----------
> > > > >Date: Thu, 16 Aug 2007 12:46:40 -0500
> > > > >From: Terry Oxandale <Toxandale@xxxxxxx>
> > > > >To: Tesla list <tesla@xxxxxxxxxx>
> > > > >Subject: RE: Ganging Variacs (fwd)
> > > > >
> > > > >There has been a great deal of discussion
> > on this issue as
> > > well as the
> > > > >parallel aspect. My experience was
> > saturation of the
> > > variac core, but
> > > > >this is based upon the core size and
> > voltage/turns ratio.
> > > I don't have
> > > > >the greatest understanding of this issue,
> > but I believe it
> > > is focused on
> > > > >the fact that only a small portion of the
> > core is used in
> > > most of these
> > > > >applications (reduce the number of turns
> > reduces which
> > > increases
> > > > >current, but also increases the
> > voltage/turns ratio to a
> > > point of
> > > > >saturation.
> > > > >
> > > > >I successfully split the core of my
> > variacs (two 1256
> > > variacs in
> > > > >parallel) to prevent this from happening
> > and have been
> > > very happy with
> > > > >the modulated current profile as compared
> > to the nearly
> > > uncontrolled
> > > > >profile previous to splitting the core.
> > It was a lot of
> > > work though.
> > > > >
> > > > >Terry
> > > > >
> > > > >-----Original Message-----
> > > > >From: Tesla list
> > [mailto:tesla@xxxxxxxxxx]
> > > > >Sent: Thursday, August 16, 2007 7:12 AM
> > > > >To: tesla@xxxxxxxxxx
> > > > >Subject: Ganging Variacs (fwd)
> > > > >
> > > > >
> > > > >---------- Forwarded message ----------
> > > > >Date: Thu, 16 Aug 2007 07:48:34 -0400
> > > > >From: timjroche@xxxxxxx
> > > > >To: tesla@xxxxxxxxxx
> > > > >Subject: Ganging Variacs
> > > > >
> > > > >I understand about using paralleling
> > chokes when using
> > > variacs for
> > > > >voltage
> > > > >control, what about for ganged series
> > variacs for current
> > > control or
> > > > >in-other-words, adjustable ballast?
> > > >
> > >
> >
> >________________________________________________________________________
> > > > >AOL now offers free email to everyone.
> > Find out more
> > > about what's free
> > > > >from AOL at AOL.com.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> >
>________________________________________________________________________________
> > >
> > > Learn.Laugh.Share. Reallivemoms is right place!
> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
>
>____________________________________________________________________________________
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