Re: Big Ferrite Transformer (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 05 Apr 2004 21:02:10 -0500
From: John Keith <jskeith@xxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Big Ferrite Transformer (fwd)

Damn, is that a cool xformer- I'm jealous! Looks like a great HV xformer,
would be a shame to rewind it.

Size-wise I'd say kilowatts, but I would advocate testing at different
voltages and frequencies for best operation. I use a hefty audio amp driven
by a signal generator for such testing, but you could also use a
TL494-driven bridge powered from a rectified and filtered variac.

Hope you make something neat with it!
John Keith



----- Original Message -----
From: "High Voltage list" <hvlist@xxxxxxxxxx>
To: <hvlist@xxxxxxxxxx>
Sent: Sunday, April 04, 2004 11:58 PM
Subject: Big Ferrite Transformer (fwd)


> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Mon, 05 Apr 2004 11:51:33 +0930
> From: Matthew Smith <matt@xxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Big Ferrite Transformer
>
> Hi All
>
> <http://www.mss.cx/ferrite.jpg> shows a large ferrite transformer that I
> acquired some time ago.  It was described as an "avionics transformer",
although
> I thought that aircraft ran on 400Hz with iron cores.  This is a big lump
of
> ferrite.  (See AA battery for scale.)
>
> The whole thing weighs 1.5kg and the low-voltage winding is a pair of
3mm^2
> conductors (bifiliar).  Turns ratio is 1:56, established by a rough
calculation
> of SQRT(L1/L2).   The HV winding is actually split into two spools.
>
> Would anyone like to hazard a guess as to the power handling of a
transformer
> like this, assuming that I drive it at 40kHz?  (I'd like to go higher, but
don't
> want to be putting all my energy into making the ferrite hot ;-)
>
> There seems to be a good few turns of paper between primary and secondary
and,
> considering the dual-spool HV side, would guess that it could take a
reasonably
> high voltage.  Should I just drop it in a tub of oil to be safe?
>
> There's a temptation to run it off-line (340V from bridge-rectified 240V)
but,
> as my physics teacher was wont to say, I think that it would have a
"short, gay,
> merry life".
>
> Thankfully, the core is held together with iron bands (not glue), so can
be
> disassembled and rewound if necessary.
>
> Cheers
>
> M
>
> --
> Matthew Smith
> Kadina Business Consultancy
> South Australia
> http://www.kbc.net.au
>
>