RE: TC Spark Energy

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

Original poster: "John H. Couture" <couturejh-at-mgte-dot-com> 


Dr. Resonance -

As you know the topic of TC spark energy has been discussed before on this
List. Little progress was made because of the confusion over the difference
between power and energy. The TC spark energy test is very simple, only an
input wattmeter and tape measure are required. The operation is continuous
and the same as typical TC operation. Just add a wattmeter at the input and
measure the spark length.

Because the operation is continuous the wattmeter (power) indicates watts
per second (energy). All you need is the number of sparks per second to find
the number of watts seconds or energy per spark. The number of equal sparks
per second is not an easy number to come by. However, it can be determined
provided the coiler adjusts the TC spark output to give 120 equal spark
lengths per second (for 60 Hz). The spark should be horizontal and to a
suitable ground.

In my test I adjusted the variac to get a continuous wattmeter reading of
120 watts or watt seconds. The sparks were adjusted until the spark was
continuous and of equal length at 120 sparks per second. Energy = watt
seconds = joules.

    Joules per spark = 120 joules/120 sparks = 1 joule per spark

The spark length was measured and found to be 8.5 inches. This then gave me
a Tesla coil rating for my Tesla coil of 8.5 inches per joule of energy.

It is obvious from the above that if the wattmeter had indicated 175 watts
with a 10 inch continuous spark and at 90 sparks per second the TC would be
rated

      175/90 = 1.94 joules per spark

      10 inch/1.94 = 5.16 inches per joule.

This TC would have been less efficient because it is producing less spark
length per joule of input energy. All very simple. So why is it that coilers
have seldom rated their TCs this way?

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 Couture

----------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, March 09, 2004 8:58 PM
To: tesla-at-pupman-dot-com
Subject: Re: TC Spark Energy


Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>



Perhaps we can all supply John with some data from each of our coils and he
could do a tabulation and find an average or statistical value.

Dr. Resonance

  >
  >
  > For over twenty years the coilers on the List have used output spark
length
  > to compare their coils. The input is usually shown as a total input
watts.
  > The problem is that this does not give the coiler any indication of the
  > actual energy per spark to give a true comparison of Tesla coils. To my
  > knowledge no coiler (see below) has ever determined the TC input energy
  > (joules) per spark for these comparisons. Do any coilers know how this
could
  > be best accomplished?
  >
  > The overall engineering efficiency is represented by
  >
  >     Percent efficiency = 100 x Spark Length/Input Energy (joules)
  >
  > The spark length could be in centimeters, inches, etc, and the input
energy
  > in joules or watt-seconds. The energy in the spark output is a complex
  > parameter so would have to be a compromise. In past postings the
approximate
  > losses in the TC system have been determined and the characteristics of
the
  > spark have been estimated. The preliminary tests I have made gave  8.5
  > inches (21.59 cm) per joule of input energy. Has any other coiler made
these
  > tests?
  >
  > John Couture
  >
  > --------------------------------
  >
  >
  >