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Re: SSTC does 10 foot sparks

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

Gerry -

I agree you cannot "get more average power out than what is coming in".
However, it is very possible to get much more pulse power out than average
power in. With Steve's TC it appears that the average power in is about 4800
watts and the pulse power out is about 300 KW giving a power gain of 62.5 .
Refer to my reply to Jim.

With a potential power output of 300 KW it is obvious that a very
long spark would be possible depending on the TC design. That is why using
power instead of energy units is not good for rating Tesla coils. It can
exagerate the output possibilities of a coil so you have to be very specific
about the input conditions.. If you use energy units you will not have this
type of problem. The energy output units will always be less than the input

"Peak power out will be larger than peak power in" is another example of the
confusion caused by using power with Tesla coils. "Peak power out" cannot be
larger than "peak power in" unless there is a time difference between the
stated powers. This means bringing in time into the process which gets you
into an energy process. It would be preferable to say that "Peak power out
will be larger than average power in".  This still requires more
explanation. The time period involved in the output vs the time period
involved in the input. And we are back again into energy out vs energy in.

Note that when using average power that you are adding time to the power
units which brings you into the energy unit solution. This has caused great
confusion for coilers in the past. Average power is actually energy because
you have to use time to find the average power. In other words when you
connect a wattmeter to the input of a TC you are measuring many parameters
depending on how you want to use them. For example the wattmeter gives you
at the TC input

   1.  wattage
   2.  average wattage
   3.  peak wattage
   4.  instantaneous wattage
   5.  volt amps
   6.  RMS wattage ??

Correctly using all of these parameters can be very confusing. You can avoid
all of the above confusion by properly using energy units to rate Tesla
coils. If the wattmeter is used as an energy meter you have to do some calcs
and you end up with different numbers compared to using it as a power meter.
For example a 100 watt wattmeter will give you 50, 100, 200, etc, watt
seconds when used as an energy meter if the times are 1/2, 1, 2, etc,

There is a much more to comparing power vs energy and I find that in some of
my past posts I have used the words incorrectly. Coilers are correct when
they say that power and energy can muddy the waters.

John Couture


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, June 18, 2004 10:42 PM
Subject: Re: SSTC does 10 foot sparks

 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 > Hi John,
 > What you say may be true, but it is misleading.  You can NOT get more
 > average power out than what is coming in.  If you could, you should get a
 > patent and become rich.  Peak power yes.  You store up energy over a large
 > time and then discharge it in a small time and the peak power out will be
 > larger than the peak power in.
 > Gerry R.
 >  > Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>
 >  >
 >  > Steve -
 >  >
 >  > Congratulations on your getting 10 foot output sparks from your SSTC
 >  > 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
 > of
 >  > your
 >  > TC can be much greater than the input of 4800 watts. This means the
 >  > efficiencies (power output/power input) of your TC  can be well over
 >  > 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
 >  > TC's in a free speech country. The pictures of those sparks show that
 >  > matter what you call them they represent a great achievement in Tesla
 >  > progress for SSTC's.
 >  >
 >  > John Couture
 >  > ---------------------------------------