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Re: Transformer Ballasting





---------- Forwarded message ----------
Date: Thu, 16 Oct 1997 21:21:21 -0500
From: Chuck Curran <ccurran-at-execpc-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Transformer Ballasting 

Hello Gwyn:

I would suggest you look at the method that has been used by quite a number
of the Coiler's who are using pole pigs or plate transformers.
Specifically, a very effective method for limiting the short circuit current
is to place the primary side of a welder in series with the pole pig
primary.  The result is a means of controlling your current draw, to the
point where using the arc current adjustment system on your stick welder
does a pretty decent job.  I would look for a welder with a rating around
225 amps output, if your intent is to work with higher power levels.  When
you do employ a welder, you must also take the welder output leads and short
them together.  I wouldn't be concerned with potential voltage drop.  The
success of many of us with this technique pretty well proves it as a
reasonable alternative.  You should also investigate using the inductance
current limiting (welder) along with a auto-transformer to vary both the
input current and the voltage.  I've always employed the auto-transformer
to run things up slowly---I don't have anything big enough to hide under to
slam a new system with full line voltage right from the start!  :^)  Some of
the coiler's have also worked with hand wound inductors with different taps
for varying the current limiting, another possible solution.  The good part
about the welder is that it is fast and effective, with the bad part being
it will cost about $190.00.  Gee, mine is 18 months old now and it has never
welded!

Chuck

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Thursday, October 16, 1997 4:21 PM
Subject: Transformer Ballasting


>
>
>---------- Forwarded message ----------
>Date: Thu, 16 Oct 1997 19:43:35 +0100
>From: Gwyn Zucca <gwyn-at-tcbod.demon.co.uk>
>To: tesla-at-pupman-dot-com
>Subject: Transformer Ballasting
>
>Hello All,
>
>I have tried searching the list archives for anything on the subject of
>current limiting power transformers, but I did not find exactly what I
>was looking for. The problem seems to be limiting the short out current
>without reducing the output voltage of the transformer. Obviously any
>resistance in circuit with the xfrm primary is going to develop a volt
>drop across it, and so the primary voltage will be lower than the rated
>output. The use of an inductive ballast, is going to have a similar
>effect. I have been experimenting with various arrangements, but have
>not yet achieved a satisfactory solution.
>
>Any thoughts, experiences on this subject would be welcome.
>
>See Ya...
>
>Gwyn
>--
>Gwyn Zucca
>ng
>