Re: Homemade HV transformer

["Finn Hammer" <f-hammer-at-post5.tele.dk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Garth!

I have made a transformet equal in size, and I can confirm that you are
right on the mark with the measurement of volts/turn, and your
assumption of power out is seems plausible. This is for continious use,
in short runs, you will be able to pull out much more, basically only
limited by the heating in the copper wire.

Since this is a dedicated Tesla Coil Supply Transformer, you might as
well build some leakage inductance into it from the start, the winding
layout shown on my webpage does that, as well as separating the primary
and secondary windings, which is nice. Run the beast under oil for best
corona controll, and cooling.

The next one that I am going to wind, will have Nomex insulation instead
of Mylar. Mylar is a great dielectric, but slippery, so that the
windings have to be kept in place with Inverted Tape at the ends, to
keep it from sliding off the interleaving. Nomex, on the other hand, is
more like a fabric, so the windings stay nicely in place.

Hope this helps a bit

Cheers, Finn Hammer

http://home5.inet.tele.dk/f-hammer/tesla/tesla.htm
goto "Homemade Pig"

Tesla list wrote:
> 
> Original poster: "Garth van Sittert" <garth-at-mediasupplies.co.za>
> 
> Can anyone help with this??
> 
> ----- Original Message -----
> From: Tesla list <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Sunday, July 30, 2000 11:57 PM
> Subject: Homemade HV transformer
> 
> > Original poster: "Garth van Sittert" <garth-at-mediasupplies.co.za>
> >
> > I have a large laminated core and bobbins only with no primary or
> secondary
> > (ie: no copper at all) that I am hoping to wind for coil use.  The core is
> 2" x
> > 2".  Bobbins are 6" high.  What sort of VA ratings could I get out of
> this,
> > 3600VA.
> >
> > So far I have calculated -at- 50 Hz 220V
> >     primary:    275 turns   (This gives me an excitation current of 10% of
> the
> > propposed max. primary current).
> >     secondary: 15000 turns (12kV -at- 300mA)
> >
> > Is this correct.
> >
> > Firstly, I wound the primary bobbin with #22 wire for test purposes about
> 400
> > turns, and then reduced the turns until I had a no load current of 1.5A
> (10% of
> > max.)  This gave me the required turns per volt.  Now I intend to wind the
> > primary with 275 turns of max guage wire I can fit onto the bobbin.
> >
> > I saw some general rule somewhere that turns per volt = 5/A where A is the
> core
> > area in sq. inches.
> >
> > Will this blow up or have I gone about this correctly.
> >
> > Thanks
> > Garth.
> >
> >
> >
> >