# Re: SSTC does 10 foot sparks

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

Jim -

I don't think it is a matter of misunderstanding. However, it is a matter of
understanding the difference between power and enegy. Coilers have struggled
with these two words for many years. If with Steve's coil the input is under
4800 watts you have the same problems when using power units for rating
Tesla coils. That is why it is better to use energy when rating Tesla coils.
Refer to my reply to Gerry.

The output power of Steve's coil as you say is very high 300KW. The ISSTC
may be very power efficient. In fact if the 4800 watts input and 300KW
output of  Steve's TC are correct the power efficiency is

Power efficiency = output power / input power
=  300 000 / 4800
= 62.5

Tesla coils can have much greater power efficiencies than this. It is less
confusing to call this power gain. Use efficiency only with energy. Note
that energy is not involved when using power units so your "making energy"
is not a problem.

John Couture

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

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, June 18, 2004 10:41 PM
Subject: Re: SSTC does 10 foot sparks

> Original poster: "Jim Mitchell" <Electrontube-at-sbcglobal-dot-net>
>
> I think you missunderstood.  Steve said the power in was UNDER 4800w
because
> his 20A fuse never blew.  I don't know how it can be possible to make
> energy, so his power output is probably less then the input ;0)  Though
> ISSTCs are pretty efficient.  The pulsed powers in the primary are around
> 300kW I believe,  but that is not the continuous average power.
>
> Regards - Jim Mitchell
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, June 18, 2004 7:34 PM
> Subject: Re: SSTC does 10 foot sparks
>
>
>  > Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>
>  >
>  > Steve -
>  >
>  > Congratulations on your getting 10 foot output sparks from your SSTC
coil
>  > with 4800 watts input. Do you know that the power output of your Tesla
> coil
>  > can be much greater than the power input? In other words the output
power
> of
>  > your
>  > TC can be much greater than the input of 4800 watts. This means the
power
>  > efficiencies (power output/power input) of your TC  can be well over
100
>  > percent. It is very difficult if not impossible to determine the true
> power
>  > input or power output for a particular output spark. The ratio of power
>  > output to power input is mostly an unknown for TC's. To my knowledge no
>  > coiler has ever properly made these measurements.
>  >
>  >   This is why it makes more engineering sense to use energy input and
> energy
>  > output in rating TC's. The energy efficiency is then equal to energy
>  > output/energy input. This efficiency is always less than one or 100
> percent
>  > and can be measured as I have shown in the past.
>  >
>  > As a final comment and to avoid muddying the waters I believe the
> statement
>  > "4800 watts input for a 10 foot spark" is an acceptable wording for
rating
>  > TC's in a free speech country. The pictures of those sparks show that
no
>  > matter what you call them they represent a great achievement in Tesla
coil
>  > progress for SSTC's.
>  >
>  > John Couture
>  > ---------------------------------------

```