Re: How should we measure coil efficiency, was neon vs. potential transformer

From: 	John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
Sent: 	Monday, July 21, 1997 6:56 PM
To: 	Tesla List
Subject: 	Re: How should we measure coil efficiency, was neon vs.  potential transformer

At 04:49 PM 7/21/97 +0000, you wrote:
>From: 	Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
>Reply To: 	bert.hickman-at-aquila-dot-com
>Sent: 	Monday, July 21, 1997 9:15 AM
>To: 	Tesla List
>Subject: 	Re: How should we measure coil efficiency, was neon vs. potential
>Tesla List wrote:

>Sometimes the quest for engineering precision may unnecessarily
>complicate the development of a straightforward way of gauging coil
>performance. Unfortunately, there are many parameters involved in Tesla
>coils that are NOT easily/directly measureable - output power, output
>voltage, and objective measures of streamer "character" (like color,
>diameter, hotness). If we can't measure something, it's very difficult
>to talk about it quantitatively(!) and comparatively - we're left with
>hand-waving and Conservation of Energy arguments. 
>John Freau's approach at least provides us with a couple of measurable
>parameters. Even if we COULD accurately measure input power and output
>power, would the most efficient coil also product the "best" performance
>as gauged by output spark length per watts in? Probably... but maybe
>However, comparing performance (Length/watt) between optimally sized
>coils may have significant merit. For every power level, there will be
>at least one coil in the population of all coils that has the greatest
>streamer length/watt. These would represent the most efficient coils in
>their power class by our sparklength/watt measurement criteria - the
>"state of the art" in coildom. However, for this to work, a consistent
>way of measuring input power and output sparklength is needed. The
>electronic opto-electronic wattmeter or simple 60 Hz analog wattmeters
>may suffice as long as we were consistent. Streamer length may require a
>more rigorous definition, like "attached streamer" not just one single
>"strike". The proposed square-law relating length to power level is not
>unreasonable... more coil data should provide more data points...
>Safe coilin' to you!
>-- Bert --

  Bert -

  I agree that engineering precision is limited when it comes to Tesla
coils. However, as I have said in the past why not set up a standard test
for the watts per foot of spark rating based from the engineering approach
instead of from some other method. The engineering approach would use the
best precision possible under the circumstances. With an agreement there
would not be less conservation of energy arguments.

 Note that the power or energy for the one shot approach or single spark
output can not be measured. What is usually mentioned is the total power or
energy for multiple sparks, not for that particular spark.

 For every power level there will be many coils in a certain population. The
coils will all have different Vp, Cp, Lp, Vs, Cs, Ls, etc, etc. An optimized
coil cannot be referred to until all of the TC parameters are taken into
consideration. For example, an optimized coil at the 1000 watt level using
12 Kv would be different than an optimized coil at the same power level
using 15 KV, etc.

 The efficiency of an optimized coil is another matter. The equation used is
as you know:

         % eff = (energy in/energy out) x 100
 Determining the watts per foot of spark length and the energy in or out are
two different types of tests using different parameters. In the past coilers
have confused these two types of tests causing the energy arguments to which
you refer.

 If sparks are to be used for the output measurements, the TC energy output
and efficiency is up for graps so coming up with these parameters is somwhat
arbitrary. I have used a system shown in my books including a graph but
there are other possibilities. Unfortunately no one I know of has come up
with something similar including a graph. However, I understand some coilers
are working on this.

 Comments welcomed

  John Couture