Re: Tesla magnifiers (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 16 Sep 2007 16:09:59 +0000
From: jhowson4@xxxxxxxxxxx
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Tesla magnifiers (fwd)

ok thanks for the help I think I might just get it, but I am going to make
sure, So basically the inductance of the 2nd and 3rd coil along with the
self capacitance of the 2nd and 3rd coil and also the top-load give the
resonant frequency of the secondary side of the TC while the primary side
remains just like any other TC.  So you want to think of it as a 2 coil
system instead of as a 3 coil system combining the 2nd and 3rd coil into 1
to do the math. Right?

Many Thanks, 
Jay
-------------- Original message -------------- 
From: "Tesla list" <tesla@xxxxxxxxxx> 

> 
> ---------- Forwarded message ---------- 
> Date: Sun, 16 Sep 2007 11:59:18 -0300 
> From: Antonio Carlos M. de Queiroz 
> To: Tesla list 
> Subject: Re: Tesla magnifiers (fwd) 
> 
> Tesla list wrote: 
> > ---------- Forwarded message ---------- 
> > Date: Sat, 15 Sep 2007 21:33:29 +0000 
> > From: jhowson4@xxxxxxxxxxx 
> > To: tesla@xxxxxxxxxx 
> > Subject: Tesla magnifiers 
> > 
> > Hello all I am researching about the tesla magnifier for an AP physics 
> > paper at school and I read a bunch of sites about how it works and I am 
> > still really confused. basically I think I understand that the primary 
> > should be of a low inductance and should have a high coupling with the 
> > secondary which should be of a slightly larger inductance, and that the 
> > point of that is to generate a high voltage through normal transformer 
> > action no resonance. This is where I am lost how is the resonant 
> > frequency of the 3rd coil found. 
> A magnifier with coils L1, L2, and L3, primary capacitor C1, 
> tertiary capacitance C3, and coupling coefficient k12 between L1 
> and L2 is equivalent to a two-coils system with: 
> C1'=C1 
> C2'=C3 
> L1'=L1 
> L2'=L2+L3 
> k12'=k12*sqrt(L2/(L2+L3)) 
> This is easy to verify by using transformer equivalent circuits. 
> The system can then be designed as a conventional coil, following 
> the tuning relation: 
> C1*L1=C3*(L2+L3) 
> The inductances can be chosen as convenient. 
> If k12' is high (>0.2), it's important to use one of the values of 
> the coupling coefficient that result in complete energy transfer. 
> This rarely happens in Tesla coils used for spark production, however. 
> 
> This works well as long as the capacitance C2 at the connection between 
> L2 and L3 is negligible. 
> If this capacitance is not negligible, it stores some energy that does 
> not go to the output. C2 can be "tuned out" with somewhat more complex 
> design formulas, that result in complete energy transfer from C1 to C3: 
> http://www.coe.ufrj.br/~acmq/tesla/magnifier.html 
> 
> > Is it a sum of the secondary inductance 
> > and the 3rd coil inductance with the capacitance of the top-load. 
> This is the correct relation, kept in the simplified and ideal design 
> formulas. Note that, as in a 
> two-coils system, the capacitance of the topload includes the effect of 
> the "self-capacitance" of 
> the third coil, that approximately adds to it. 
> > Or is 
> > it just the 3rd coil and its top-load giving the resonant frequency. and 
> > how is this frequency produced. Is the driver circuit frequency the same 
> > as the resonant frequency of the 3rd coil and it is just having the 
> > voltage increased by the secondary which is feeding the 3rd coil or what 
> The driver resonance frequency is the resonance frequency of the 
> combination L2+L3 and C3. 
> The voltage that appears at the top of L2 is not related directly by 
> "transformer action" to the other 
> voltages, unless the coupling coefficient k12 is very high, what is 
> usually not feasible. 
> The magnifier is useful in energy conversion applications, because it 
> allows very fast energy 
> transfer without excessive proximity between the primary circuit and the 
> output terminal. For 
> spark production, the main advantage appears to be just the separation 
> between the driver and 
> the output coil. The system can be designed in a way that allows C2 to 
> be just the distributed 
> capacitance present at the connection between L2 and L3, but then the 
> effect of C2 is already 
> small, and the simplest approximation can be used. 
> 
> Antonio Carlos M. de Queiroz 
> 
> 
> 
>