RE: The "second pig" ballast: Questions.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>

Thanks, Steve.

Well, the core *is* in two pieces already :)  The two
spools are separatly bound with steel straps, then
bound together side-by-side with another pair of
straps.  I'd be happy with a 3-5kVA ballast to start
with, so perhaps I only need to mess with half of the
core anyway.  Unfortunately, I'm still a bit unsure as
to how I'd go about introducing an air gap without
either letting the thing fly into pieces or without
the laminations simply filling the cut as I go.

So, a quick physics lesson on why the air gap is so
critical would be interesting (at least to me).  My
mental model of an inductor is obviously
over-simplified.

On the other hand, perhaps I should *let* it fly
apart, then just use the laminations as core material
for a "sliding choke"-type ballast.  There's certainly
an abundance of good steel here...

Aaron

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Steve Conner"
> <steve.conner@xxxxxxxxxxx>
>
>  >The core consists of two separate "spools" of
> steel (not
>  >E's and I's, although the whole core has two
> "windows"
>  >like an "EI" core), and won't come apart in any
> way
>  >which might make winding easy.  Bummer.
>
>
> Bummer is the word. If you can't take the core
> apart, then you can't
> introduce an air gap to it, so you'll find it
> impossible to make an
> efficient ballast no matter what number of turns you
> use.
>
> If it were me I would be thinking of sawing the core
> in half (after binding
> it in a suitable way so it won't spring apart
> violently)
>
>
> Steve C.
>
>
>