[Prev][Next][Index][Thread]
Re: 50%
Tesla List wrote:
>
> >From couturejh-at-worldnet.att-dot-netTue Oct 29 22:52:39 1996
> Date: Tue, 29 Oct 1996 22:14:10 +0000
> From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: 50%
>
> At 05:25 AM 10/29/96 +0000, you wrote:
> >From hullr-at-whitlock-dot-comMon Oct 28 21:48:14 1996
> >Date: Mon, 28 Oct 1996 12:43:40 -0800
> >From: Richard Hull <hullr-at-whitlock-dot-com>
> >To: tesla-at-pupman-dot-com
> >Subject: 50%
> >
> >All,
> >
> >In theory, We should never be more than 50% efficient in energy transfer
> >from one capacitor to another! i.e. the Cprimary to the Csecondary
> >Usually the resonator load capacitance plus Ion cloud loading. This
> >assumes 100% coupling and zero other losses! If fact, we are much lower
> >than that with the finest system in operation.
> >
> >50% of the capacitively stored energy always disappears in circuit loses
> >(resistive and magnetic) even with direct wired connections. There is a
> >lot of additional wasteful garbage going on in between the primary and
> >secondary capacitors.
> >
> >Richard Hull, TCBOR
> >
> ---------------------------------------
>
> Richard -
>
> I believe the 50% you refer to is for the 50% maximum current or power at
> critical coupling. Power transformers with iron cores can be up to 98%
> overall energy efficient (coupling is almost 100%). Air core transformers
> are much lower in efficiency. Tesla coil transformars appear to be about 10%
> for large coils to 80% for small coils overall energy efficient (coupling is
> usually less than 50%). Note that all energy losses are resistive and not
> reactive.
>
> The watts (seconds) necessary to produce a foot of spark is a good way to
> measure this energy efficiency because most coilers measure the watts and
> spark length and there is a lot of good data available. The spark length,
> however, should be a controlled spark length, not the usual streamer.
>
> The only Tesla coil efficiency graph that I know of is the one in my Tesla
> Coil Notebook. This graph is based on the Watts per Foot of Spark concept
> that I posted Oct 9, 96 under 'Power and Efficiency'. All this information
> is shown in the JHCTES computer printouts in the TCC Guide.
>
> Except for this graph I have not seen any Tesla coil data with CACULATIONS
> from coilers who measure their coils for energy efficiency. I show in the
> TCC Guide how I measured one of my coils at 56% efficiency. The smaller coil
> I also show in this book would be more efficient.
>
> It should be noted that my graph is based on very limited data. I would
> appreciate receiving data of this type from other coilers. I would change
> the graph if this data indicated something different.
>
> Jack Couture
> 10823 New Salem Point
> San Diego, CA 92126
Jack,
I am sorry but I would rather consult a medium that rely on the old saw
of watts/foot of spark for a gauge of anything other than to know from
experience whether based on coil size, experience of the builder, and
material used, whether a coil is doing- terrrible, OK, or pretty good.
Those three data points are about as much as I might want to glean from
so tenuous a source as watts per foot of arc! There are just too many
other variables in the bottom line outputs from various coils! It is
very tempting and seductive to use these two parameter though as the
watts into the system can be relativley easily obtained and the visual
spark length out is also a very measurable quantity. Unlike you I have
never seen anything approaching a good method of obtaining any data
whatsoever which can fix the relative efficientcy of these highly
variable multi-variant systems to a decent engineering level of usage!
I have seen a 5KVA coil produce thin whispy sparks out to 7-8 feet. I
have also seen and constructed systems which used the same power level
and produced sparks of the same length or longer which are flaming white
hot tongues of elecrical energy. It is patently obvious, from my
experience, that simple spark length bears virtually no relation to
efficiency without knowing a lot of other key variables right down to
the "cut of the jib" of the builder/operator.
The only thing I would suggest is that virtually all of the energy out
of the fun type coil system is in the form of resistive heating losses
(sparks dissapatting their energy in air) and that a good closed bomb
calorimetry measure of the rise in air tempearture of the surrounding
air would yield a very acceptable, if not virtually impossible to
measure, merit figure of the true output from one of these systems.
The eye told us, from the above offered comparison, that there was more
efficacy of energy transfer in the white hot 7-8 foot arcs over the thin
and whispy 7-8 footers at the same 5KVA level of operation. I am
confident that calorimetry would quantitatively confirm this
initial qualitative finding!
Richard Hull, TCBOR