# Re: power v energy measurements, was Re: SSTC does 10 foot sparks

```Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>

Gerry -

Congratulations. You have beaten my TC spark record.
How did you measure the sparks?
What were the parameters of your coil?
You have found that the coil size makes a big difference.

You do not double the spark length if you double the joules. It is the coil
that determines how much the spark increases in length (if I understand you
correctly).

This method gives a known amount of input energy for each spark at a certain
length. This is not possible with random length sparks. You can then make a
fair comparison of  TC's  with this method.

There is much more to consider. Do you have any suggestions for improving
this method of comparing TC's?

John Couture

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

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, June 25, 2004 8:54 AM
Subject: Re: power v energy measurements, was Re: SSTC does 10 foot sparks

> Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
>
> Hi John,
>
> My first coil (a small one) pulled 65 watts at 140VAC and produced 11 inch
> power arc at 120 BPS.  Using your process:
>
> 1.  65 watts for one second or 65 joules in one second.
> 2.  120 sparks for one second.
> 3.  65 joules/120 sparks = 0.54 joules per spark
> 4.  11 inch arc
> 5.  20.4 inches per joule.
>
> Now using the JF equation:  1.7 * sqrt (65watts) = 13.7 inches.  I didn't
> consider my coil all that efficient.
>
> I think one problem with inches per joule is this implies that if you
double
> the joules, you double the inches which many of us know to not be true.
> John Freau empirically derived equation suggest this is the case.
>
> Example: Take a TC designed for 120 BPS at some power level.  Double the
> power and double the Cp to keep BPS at 120.  Now the bang energy has just
> doubled but the spark has only increased by a factor of sqrt2.  One could
> conclude that a large powered coil would yield a lower inches per joule
and
> a small powered coil would favor a larger inches per joule.  The system is
> just not linear.
>
> Gerry R
>
>  > Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>
>  >
>  > The calcs for my test were as follows.
>  > 1. My coil wattmeter showed 120 watts for one second or 120 joules in
one
>  > second.
>  > 2. My coil output was 120 sparks for one second.
>  > 3. This gave 120 joules/120 sparks = one joule produced one spark
>  > 4. The spark was 8.25 inches long,
>  > 5. This gave 8.25 inches / one joule = 8.24 inches of spark for one
joule
> of
>  > energy input.
>  >
>  > If you substitute the variables of any size or type of coil correctly
and
> do
>  > the math correctly as above you will find that the 8.25 inches is a
record
>  > that is hard to beat.
>  >
>  > All comments -  please show your calcs as outlined 1 to 5 above so I
will
>  > understand what you mean..
>  >
>  >   John Couture
>  >
>
>
>

```