Re: secondary core other than air

["Garth van Sittert" <garth-at-mediasupplies.co.za> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Aren't ferrite cores used in radio reception which ranges in the megahertz?

I think the atoms would not be able
> to spring back into their original orientation once the magentic field
> collapes fast enough.

I thought that eddy currents induced in normal iron cores is the major
disadvantage that is overcome by using powdered iron that reduces the
conductor length in each piece of iron in the core.  Thus the induced emf
across each piece of iron is very small thus having negligable currents in
the core.

My R1's worth.  Not much!  R7 to $1 here in South Africa.

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, August 07, 2000 7:38 PM
Subject: Re: secondary core other than air


> Original poster: "Garry F." <garryfre-at-pacbell-dot-net>
>
> I often thought the reason telsa coils were air core was because Ferrite
> might not be capable of rapid magnetic change that would be required for a
> high frequency app such as tesla coils. I think the atoms would not be
able
> to spring back into their original orientation once the magentic field
> collapes fast enough.
>
> I could be wrong tho, but I tend to think this is why they reccommend only
> non-magnetic wire as conductors in Tesla coils
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Sunday, August 06, 2000 2:04 PM
> Subject: Re: secondary core other than air
>
>
> > Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
> >
> > Hi Garth,
> >
> >         #21 enameled magnet wire is about 33.1 turns per inch.  So you
> probably
> > have #21 which is fine.
> >
> >         Don't worry about only 5 turns on the primary.  Just tune your
> coil
> > with
> > what you have and all should work fine.
> >
> >         I don't know of any way of lowering the secondary frequency
short
> of a
> > bigger or more top load.  Ferrites in or around the secondary are not
> > impossible, but that would take a lot of thought and design.  Perhaps a
> fun
> > project but too messy in this case.  Just tune with what you have and
all
> will
> > be well.
> >
> > Cheers,
> >
> >         Terry
> >
> >
> > At 03:09 PM 8/6/00 +0200, you wrote:
> > >
> > > Would it be possible to use something other than an air core to
increase
> the
> > > secondary inductance and Q factor?
> > >
> > > Are their any possible cores available?  I know something like ferrite
> core
> > > would create internal arcs, but surely there must be something out
> there!
> > >
> > > I have just wound my 6.4" secondary with what I was told to be #24
wire,
> but
> > > wintesla seems to use incorrect figures for wire guage and turns per
> inch.
> > > My secondary has 33 turns/inch.
> > >
> > > My secondary inductance is way too low and I now have re-calculated my
> > > primary with only 5 turns which I think will be terrible for spark gap
> > > losses.  My topload is 20" wide so I can't drop secondary resonance
any
> more
> > > unless I use some secondary core other than air or wind more turns on
> the
> > > secondary.
> >
> >
> >
> >
>
>
>
>