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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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>>
>>
>>
>>
>>________________________________________________________________________
>>AOL now offers free email to everyone.  Find out more about what's 
>>free from AOL at AOL.com.
>>    
>>
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>