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Re: Output/Input
to: John
Your efficiencies in the 50% range are very close to those predicted in
David Sloan's papers on Resonance Transformers, and with only around 50%
efficiency possible in the classic loose coupled circuit, this is the
reason he used the series fed resonance transformer with tight coupling to
acheive efficiencies in the 85% range. A small portion of the bottom of
the 18 turn copper secondary inductor was tapped and direct coupling used
to feed the monster. Output was 1 MEV at 100 kW -- not bad for a vacuum
tube coil.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Output/Input
> Date: Monday, January 11, 1999 6:56 PM
>
> Original Poster: "John H. Couture" <COUTUREJH-at-worldnet.att-dot-net>
>
>
> Bart -
>
> Tesla coil efficiency has been discussed on the Tesla List in the past
but
> is not popular with coilers especially advanced coilers.. The problem is
> that large Tesla coils have low efficiency and reveiling this information
> tends to detract from the glamour of big sparks. I do not mean to
belittle
> large coils because big sparks are impressive and require skill and
> craftmanship but this is in lieu of TC engineering.
>
> If you are referring to overall efficiency you must find "energy
> out/energy in" not "power out/power in" for your Tesla coils. The energy
> efficiency is always under 100% but the power efficiency (gain) can be
over
> one thousand percent.
>
> Note that the two equations you show are energy equations for the
energy
> in the TC primary and secondary capacitors. These equations should only
be
> used with controlled sparks because the random variable sparks indicate
> variable energies in the capacitors that cannot be directly related to
the
> input watts of the TC.
>
> The only published information I know of for builing a Tesla coil and
> testing it for overall efficiency is shown in my books. Also shown is the
> JHCTES computer printout of this coil plus a TC efficiency graph for all
> coils is shown.
>
> Some of the details are:
>
> 225 watts - 7.5 KV - 30 ma neon transformer
> 250 KV - estimated secondary terminal voltage
> 389 input watts per foot of spark
> 51% - overall efficiency - JHCTES printout
> 53% - overall efficiency - from graph
> 56% - overall efficiency - from test shown in book
>
> These efficiencies for the coil are amazingly close considering they
were
> obtained by completely different methods. This inforrmation is
preliminary
> and limited but cannot be verified because apparently no one has gone
this
> far into TC engineering for efficiencies and published the information.
>
> When changes are made in the coil and the spark increases, the before
and
> after efficiencies should be found to be certain the increase was not due
to
> something else that changed the efficiency. This is espescially true for
> changes in the operating spark gap, etc.
>
> It is obvious that there is plenty of additional TC engineering work to
be
> done. The Tesla List is the best place to coordinate this work and report
> progreass.
>
> John Couture
>
> -------------------------------
>
>
>
>
>
> At 01:47 PM 1/10/99 -0700, you wrote:
> >Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>
> >
> >What is the best method for measuring efficiency?
> >
> >Eff = Output / Input. How is this accomplished. I would
> >think some calculation must come into play. If we know
> >our power in, how can we measure our power out?
> >
> >Pout = .5 * Cs * (Vout^2) * BPS.
> >Pin = .5 * Cp * (Vcap^2) * BPS.
> >
> >We have equations, but this all appears a bit difficult
> >to measure. Pout / Pin is meaningless without a true
> >measure of Vout. I can't see the arc length as a good
> >measure of power out either since arc characteristics
> >are far more than simply the length. What about the
> >diameter and intensity?
> >
> >I've seen posts on efficiency's hitting 80% on good
> >designs, but how do you guys measure efficiency?
> >
> >Bart
> >
> >
> >
> >
> >
>