Re: Practical Magnifier Design ? ?

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

Original poster: "colin.heath4" <colin.heath4-at-ntlworld-dot-com> 

hi john,
             i think the only gains over a 2 coil system is you can use a
smaller cap for a given arc length(although this is probarbly due to the
higher voltage used to drive maggies).
and also the arc length compared to resonator length(if you dont include the
secondary in the equation)
i am building one at present though as there is nothing like proving it for
yourself.
cheers
colin

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, October 12, 2003 2:50 PM
Subject: Re: Practical Magnifier Design ? ?


 > Original poster: FutureT-at-aol-dot-com
 >
 > Chris,
 >
 > The ratio of inductance between the secondary and resonator is an
 > important consideration for magnifier design.  If the ratio is low, a
 > higher voltage will be produced at the top of the secondary, and
 > excessive corona or driver flashovers are likely.  If the ratio is high
 > (small secondary inductance, large resonator inductance), the
 > coil will be better behaved, but will require a tighter driver coupling,
 > to obtain sufficient overall system coupling.  I've used ratios from
 > 1:2 to 1:10 in my experimental magnifiers.  It can be seen from this
 > that a best compromise ratio must be used for best results.
 > Antonio's formulas may naturally lead to a particular ratio.
 >
 > In my magnifier work, I never saw any efficiency improvement compared
 > to a normal 2-coil Tesla coil.  I did not do any tests over 5kW.  In one
 > experiment, I placed the resonator directly on top of the secondary,
 > thereby changing the coil to a 2-coil system, and the spark length
 > increased by 1".
 >
 > To fully take advantage of Antonio's proposals, the gap must have
 > excellent quenching.  It's not clear if such quenching can be practically
 > achieved without excessive gap losses.  It's not clear to me if the
 > achieved spark length depends more on the initial resonator ring up
 > energy, or if it depends on the entire energy over the ring-down period.
 > If the initial energy is the key, then Antonio's method may provide more
 > of a benefit, even if the quenching is marginal.
 >
 > Generally the driver is built rather large, to permit the use of thicker
 > wire to reduce losses, since the current is high in the driver.  The
 > resonator which sees a lower current, can tolerate the use of thinner
 > wire.  For example in one design, I used 140 turns of 18awg wire in the
 > secondary which was 11" diameter by 10" tall (the winding).  The
 > secondary was 10" diameter by 13" tall, and was wound with 24awg
 > wire.  This coil was run at 600 watts to 5000 watts or so.  I tried
 > various series quenching rotary gaps, but they gave no advantage over
 > a normal rotary.
 >
 > The behaviour and performance of a typical magifier is very similar
 > to that of a normal 2-coil Tesla coil.  In some cases, the physical
 > layout of the magnifier design can be helpful for fitting the coil into
 > a particular building, etc, compared to a 2-coil classic system.
 >
 > John
 >
 >
 > >But if anyone has any very practical information or a resource I could
 > >tap (without being too overwhelmed with "super hardcore" t! heory) I'd
 > >appreciate it. By practical information, I mean general rules, design
 > >equations, rules of thumb, construction tips, etc...)
 > >
 > >Thanks
 > >
 > >-Chris
 > >
 > >
 >
 >
 >
 >
 >