Re: [TCML] Re:Pros and cons

[Steve Ward <steve.ward@xxxxxxxxx>]

Yes, the 74J i see is just the peak energy stored in the primary capacitance
in Finn's case.  Indeed the real spark energy (time integral of the spark
power during 1 spark event) is certainly higher than 74J (unless of course
he is recycling nearly all of his primary energy, i doubt it).

There is something unusual about Finn's system, at least compared to mine
(which is a bit smaller, but similar spark length).  My primary current is
only 1300A when using a 1.25uF tank capacitance at 35khz.  I calculate (just
for comparison) that the peak primary energy is only 14J in this case (not
the true bang energy!).  The best sparks were about 12 feet in length but
surely not at a low 67bps!  I think i see peak performance at about 250bps.
The DC bus power consumption is about 6.5kW in this case or about 26J/bang
(so nearly 2X the peak primary energy).  When you compare this to other
topologies you can see the benefit in reduced peak current/voltage capacity
of your primary components, with of course the trade-off that the slightly
lower current/voltage persists for a longer period of time.

Steve



On Mon, Dec 14, 2009 at 4:56 AM, <uhvsystems@xxxxxxxx> wrote:

>
> Finn,
> Quick & dirty analysis.
> Damping of the secondary oscillations of the high peak power tesla coils
> seems to indicate quality factors Q=10-15 due to spark loading
> dissipation.From that,geometry of your coil and the data you kindly provided
> some things can be concluded.Althought Q-factor for LCR circuits with
> nonlinear load (ie. sparks) can not be correctly defined,it is my assumption
> in the aproximation limit analysis for tesla coil that does not matters
> much.Setting Q~10,Prms>6 kW,n=58 pps,number of "ring up cycles"=6.5,Csec~80
> pF results in the output potential of your coil Usec>800 kV.I don't exclude
> possibility that this is really a 1000 kV tesla coil.
> BTW,bang 74 J in the primary is somewhat misleading here.This is DRSSTC and
> most likely the coil is given well over 100 J per impulse.
>
> Regards,
> Fez Zaev
>
>
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Finn Hammer wrote:
>
>
>
> > What is the driving resonant frequency,time to secondary peak voltage,and
> input rms power of your DRSSTC?
> >
>  32kHz, 200µS, Havent measured input power, but below 11.5kVA, due to 16A
> fuses holding up.
> Primary current topping up at 3kA, so voltage across 1.5µF cap = 9950V,
> bang 74Joule
>
> Cheers, Finn Hammer
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