Re: [TCML] Paralleling chokes for 1256D's

[Steve Ward <steve.ward@xxxxxxxxx>]

You cant equate the 4 transformer thing to a single core circuit.  The
4 transformers have their outputs in series which forces *current* to
be the same through each winding, but the *voltage* can be whatever is
required.  So because of this observation that  4-core system can be
operating at 4 different flux levels simultaneously means that any
"single core" implementation would simply not play by the same rules.

Transformers can be tricky.  Be sure you are thinking clearly about
how they behave.  All windings should see the same volts/turn.  If you
are designing a transformer where that is not true (such as your
proposed single core to balance 4 varaics) then you will run into very
large circulating currents due to flux imbalances generated by the
windings.

Thinking in terms of currents can be tricky.  You must clearly
understand the difference between the magnetizing current (the part
that merely magnetizes the core), and the load current, which is
coupled via mutual inductance to another winding, hence its flux
contribution to the core is zero.

Steve


On Thu, Dec 6, 2012 at 7:30 AM, drieben <drieben@xxxxxxx> wrote:
> Hi Scot,
>
> It would seem to me that the only limiting factor here would be
> the physical size of your choke's core and getting all of that #4
> or #6 THNN wire for 4 variacs inside that single core. But
> electrically, I'm seeing it the same way that you do ;^) BTW,
> it's my understanding that there is normally 1 choke for every
> 2 varaics paralleled, not 1 for 1. The 4-stack 1256D inside
> my big coil's control panel came with just 2 paralleling choke
> pre-installed and that is the way that I have seen other 1256D
> stacks pre-assembled as well. But yes, if you can get your
> choke's core large enough, I don't see why you can't use just
> one.
>
> David
>
> ----- Original Message ----- From: "mr. scot dingman"
> <1stbunnykiller@xxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Wednesday, December 05, 2012 4:04 PM
> Subject: [TCML] Paralleling chokes for 1256D's
>
>
>
>> hey all,
>>
>> Im getting ready to "re-parallel" my 1256ds into all 4 being paralled at
>> 240 V resulting in 0-280 at approximately 115A.  According to the info I
>> have, I will require 4 paralleling chokes to do this. Each variac has it
>> own choke. But heres my thought, each variac has its own choke  but the
>> paralleling winding is in series to all four chokes
>> see:
>>
>> http://www.webring.org/hub?ring=teslaring;id=354;ac=L%7BeQEM%B8%AD%9C%83%F0%E2%9C%86%88%7Fi%1D%1Al%26%28%1AU%EB%F2%C9%DF%B2%A0%A8%9F%91xaT%1C.%2B%28E%1A%A9%E1%8D%D2%CB%A2%B4%91%9Dl%7FMJO;go
>>
>> page 31 connection 2 diagram for the suggested manner of wiring.
>>
>> why couldnt i use 1 core, wrap each output from each variac on the single
>> core and wrap the paralleling winding on the same core?? Am I missing
>> something here amoungst my thoughts and theory or will i have a variac
>> meltdown??
>>
>> Scot D
>> _______________________________________________
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>
>
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