RE: TC Spark Energy

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

Original poster: Dave Leddon <leddon1-at-llnl.gov> 

At 11:08 AM 3/11/2004, you wrote:
>Original poster: "John H. Couture" <couturejh-at-mgte-dot-com>
>
>John F. -
>
>I agree the spark length is a non linear function of the input wattage and
>the overall energy efficiency of a Tesla coil is equal to
>
>    Efficiency = output energy/input energy
>
>The input energy is easy to find but the output energy is a problem when the
>output is a spark length. I agree that for a certain spark length the energy
>varies depending on the thickness and brightness. But how do you determine
>the joules of energy with varying spark thickness and brightness? The spark
>energy could also be determined by voltage, current, and time as one coiler
>mentioned. To my knowledge no coiler has ever made these tests.
>
>John Couture
>
>----------------------------------
Couldn't we resort to some crude form of calorimetry to determine the 
energy in the arc?  It would seem to me that if you allow a known number of 
arcs to strike a copper target while keeping track of the temperature rise 
in the metal and then, knowing the mass of the target, you could directly 
compute the number of joules absorbed.  And if you were concerned about the 
energy lost to the atmosphere through heat, light and sound, you could 
improve the measurement by enclosing the target and the entire arc path 
inside an insulated cylinder.  This might make a nice Science Fair project 
for somebody.

Dave
Pleasanton, CA


>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Thursday, March 11, 2004 9:20 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: TC Spark Energy
>
>
>Original poster: FutureT-at-aol-dot-com
>
>In a message dated 3/10/04 7:14:51 PM Eastern Standard Time,
>tesla-at-pupman-dot-com writes:
>
> >The answer is also very simple. This rating method gives low ratings for
> >large TCs,  only a couple inches per input joule. In other words large TCs
> >appear to be very inefficient. This is a problem. Any comments?
>
>
>John,
>
>This is because the ratio of spark length to input power (or energy)
>is not linear.
>Rather the relationship follows the square law closely.  I don't
>see this as a matter of efficiency or inefficiency.  Efficiency is
>the ratio of input energy to output energy.  The sparks from a large
>coil are not only longer but thicker and brighter in a sense.  This
>takes a lot of energy to produce such sparks.  Your methods
>would be true only for a particular spark length.  For example
>you could compare a coil that gives a 10" spark with another
>coil that gives a 10" spark.  You could judge the relative
>efficiencies of these two coils by measuring their input power.
>
>John F.


***************************************************************************
David H. Leddon