Re: Silly question?

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Godfrey,

Tx for the link I need to find a better way to index my bookmark
;-( I think the heat problem you find in your tran. is probably
cause by the spot welding: You created short and change the
structure of the alloy at these point ( tempering ).

If one day if I could find 4 pieces of 4" X 4" core by 2' long
I'll try to build a research trans. may be with the top core
easily detachable for secondary removing and build couple of
secondary one really low voltage for spot welding a 35 V for
welding a 300V for plasma and a 15 KV for tesla. But for now I
juste find 6" long piece at scrap yard it come from a company
they scrap old trans. but refused to sell; the utility company
not allowing it, they saw trans. in small piece for metal
recovering :-((

Cheers,

Luc Benard
  
Tesla list wrote:
> 
> Original poster: "Loudner, Godfrey by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>
> 
> Hi Luc
> 
> The site that shows the homebrew pig is located at
> http://www2-dot-netdoor-dot-com/~maxz . The core is constructed by gluing together
> the cores of small transformers. I collected a pile of transformers used to
> supply street vapor lamps. The power company here does not care if you dig
> in their dumpsters. The cores are easy to get apart with a hacksaw. I made a
> good size square core by spot welding the cores together. I experimented by
> using the existing primaries. By using a secondary with about 20 turns, I
> found that the voltage output varied a lot when I changed the position of
> the coil. I concluded that the performance of such a core was too erratic to
> predetermine a set of design parameters. Also the core had a number of hot
> spots during operation. Even though I made the core very uniform, it
> probably had a complex of eddy currents. I am willing to bet that the wave
> shapes of the output did not look anything like those of 60 cycles/sec. The
> charging of a tank cap would be very erratic. In fact the owner of the site
> e-mailed me that the transformer worked, but it blew his tank cap. I don't
> know if rectifying the output of such a transformer would improve very much
> the charging of the cap. By the way, it took the owner of the site 14 months
> to hand wind the secondary.
> 
> Godfrey Loudner
> 
> > -----Original Message-----
> > From: Tesla list [SMTP:tesla-at-pupman-dot-com]
> > Sent: Wednesday, September 26, 2001 11:14 PM
> > To:   tesla-at-pupman-dot-com
> > Subject:      Re: Silly question?
> >
> > Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <ludev-at-videotron.ca>
> >
> > Hi Matthew,
> >
> > No it's not a silly question, but I could show you some reason
> > why most of us don't build trans. First the difficulty to find a
> > core and don't think about making one with steel sheet; trans.
> > mfg. used a special kind of alloy commonly call silicon steel not
> > so expensive but hard to find; they are the only one using this
> > stuff, the sheet received a surface treatment to make it no
> > conductor, this surface treatment need to resist to kind of high
> > temperature. If they don't build the core this way the loss are
> > incredibly high. An other thing; the mfg. wind there coil in a
> > way that the oil could circulated in it, pig are nice piece of
> > engineering.
> >
> > BUT...! But some do what you plan to do, I remember a member of
> > this list, a Finnish I think, he made a core, he build a form in
> > Plexiglas and fill it with small piece of microwave trans. core
> > glue together with epoxy. I don't know what was the result may be
> > other member have better memory than me. I'm a kink of "do it
> > your self" guy but for a big trans. no thanks.
> >
> > Often you can find a nice core from a welding machine but the
> > window are to small for high voltage coil remember in a HV coil
> > you need a lot of insulation and this take place.
> >
> > I try to find one here in Quebec Canada but no success for now
> > they are easy to find used in USA for around $ 300.00 to $400.00
> > but could you imagine the cost of shipping and I don't know about
> > the custom charge....
> >
> > Cheers,
> >
> > Luc Benard
> >
> >
> >
> > Tesla list wrote:
> > >
> > > Original poster: "Matthew Smith by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>
> > >
> > > Hi All
> > >
> > > Maybe I've been away from electrical engineering for too long and
> > > writing software as made me soft in the head - but:
> > >
> > > If sourcing suitable 110/240V --> xkV transformers is such a bind, why
> > > not wind our own?  If it's a question of it being too (mechanically)
> > > difficult, maybe I (and others) should try to devise a tranny winding
> > > gadget - possibly one that's flexible enough to do Tesla secondaries as
> > > well...
> > >
> > > In my previous engineering incarnation, we were forever getting motor
> > > stators rewound and they must be a NIGHTMARE to do compared with a
> > > tranny!
> > >
> > > Transformers with alternated laminations (ie the ones that won't pull
> > > apart) are obviously out of the question...
> > >
> > > If anybody's seen the little widgets on sewing machines that fill the
> > > underside bobbin, maybe something based on that principle?
> > >
> > > Cheers
> > >
> > > M
> > >
> > > --
> > > Matthew Smith
> > > Kadina, S. Australia
> >
> >