Re: TC efficiency, was Math help...

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 7/17/01 12:56:12 AM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

> Original poster: "John H. Couture by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" 
> <couturejh-at-worldnet.att-dot-net>

John C,

As Bert pointed out, we can easily compare the relative
"efficiencies" of various coils.  For instance if our goal is long
sparks, and one coils gives 40" sparks with 600 watts, and 
another gives 60" sparks with 600 watts, that's saying something!
True, we still don't know the true efficiency from an input vs.
output energy point of view, but we at least know that one coil
is "better" at producing long sparks than the other.  This kind
of knowledge allows us to improve our coils.  This is how
I've been approaching the "efficiency" question for now.  I realize
this is not a true efficiency measurement from an rigid engineering
standpoint.  We actually don't need to know the true efficiency to
improve or design our coils (but certainly it would be nice to know).

Knowledge of spark characteristics in air is actually very useful
towards determining the true efficiency of a TC.  If you know how
much energy the sparks are burning up, you simply subtract this from
the input energy, and voila, you have the true efficiency, at least from
the point of view of the % energy delivered to the load.  This is why
analyses such as Bert's discussion of leader formation and energy
requirements are important towards calculating the true efficiency
of a TC.  It is interesting however, that in a TC, the input power vs.
spark length is often a more useful concept than the true efficiency.
This may seem strange..... but it's true.  The reason is due to our
goal of long sparks.  Consider a coil that has very high true efficiency,
but gives short sparks (perhaps because there are too many of them,
or they are very fat).  Compare this with a coil that has a lower true
efficiency, but gives longer sparks for the same input power. Most
coilers would consider this second coil to be "better" towards 
achieving the goal of long sparks.

How would *you* suggest measuring the true efficiency of a TC?
I forget how you set up your test that you mentioned some
time ago.

John Freau
---
 
>  
>  
>  John F. -
>  
>  When I said to forget the spark characteristics in air it was because as in
>  the past discussions on the List this only complicates the understanding of
>  the subject and no progress is made. The basics are difficult enough to
>  understand without complicating the discussion.
>  
>  I will be interested in your results when you find the time to test you
>  coils for efficiency. Apparently no other coilers are making these tests. 
If
>  Tesla coils are to be improved the  understanding of how to increase the
>  efficiency of the TC is of utmost importance.
>  
>  John Couture
>