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Re: Ganging Variacs (fwd)
---------- Forwarded message ----------
Date: Sat, 18 Aug 2007 18:37:28 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Ganging Variacs (fwd)
Hi Frank,
Paralleling variacs has been done by many (I personally haven't) and
requires balancing chokes.
Check this out:
http://bellsouthpwp.net/B/u/BunnyKiller/parallel.html
Take care,
Bart
Tesla list wrote:
>---------- 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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>>
>>
>>
>>
>>________________________________________________________________________
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>>
>>
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