Re: homebrew hv

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <presence-at-churchofinformationwarfare-dot-org>

That is an interesting transformer. The core is close to that of a polemount
transformer. They use "step lap" cores. They wind a strip of good steel
around a bobbin to give it a fun shape. Then they unwind it and chop the
strip into pieces so that it can be assembled around a wound coil assembly.
They cut the core apart so the edges don't all meet in the same place like
in the transformer you have. They alternate so they fit like bricks in a
brick wall. Then they strap the core together and you end up with a really
low loss transformer. All distribution transformers are always on and always
using power even if you are not, so effeciency is of interest to utilities.

KEN



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, September 29, 2001 1:27 PM
Subject: homebrew hv


> Original poster: "Metlicka Marc by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
>
> All,
> Last night i pulled one of the 40-1 transformers apart:
> http://www.fortunecity-dot-com/meltingpot/syria/1210/id26.htm
> They are held together with steel strapping and the cores slid out very
> nicely. The cores are really well constructed, looks like they may have
> been pressed into shape? They are actually 1"t x 2.5"w x 12"h with a
> 4.5" outside core width.
> There are a few things i want to ask for help on:
> first is whether this seems like a good core to wind a hv transformer
> on?
> i am thinking of a large nst type transformer using a hv winding on each
> outer leg and the primary on the center. The thing is that the original
> transformer has both windings around the center lag, maybe because all
> the flux travels through this doubled section? so will the windings on
> the outer legs see enough magnetic flux to generate the hv, I'm shooting
> for 20 kv each using and 41675 turns of 22g wire each. This would need
> 250 turns of primary wire (if my calcs are right?) or would it be a
> better idea to wind one single hv winding with the primary in the center
> like the original? I'm just not experienced enough to know.
>
> second is that with the large taps of the originals secondary windings,
> and the fact that two cores doubled up fit right into the hole of the
> big winding, and the fact that i could gap the core with shims, could
> this make a good high current inductor?
> I will check the inductance of this core, but i was wondering if anyone
> could give me an idea of what it should be for a nice 100+ amp current
> limiting reactor?
> The center core area would be 12" but capable, the taps are 250 amp
> rated so it looks like at least a 150 amp rating for the windings?
> I will post more data as it comes, but i'm hopping for some input from
> the list on these tesla projects? (i hope, i hope)
> Thanks,
> Marc
>
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