Re: SSTC does 10 foot sparks

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

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

John -

I think it is a matter of deciding how to handle the Tesla coil output when
the output is in sparks. Maybe we should just test the TC output with a
resistive load like most electrical generators are tested. Loading the TC
output reduces the voltage to any voltage and current combination you want.
The input and output would be continuous and easy to measure. This has been
suggested in the past but there was not much coiler interest.

John Couture

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


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, June 23, 2004 11:48 PM
Subject: Re: SSTC does 10 foot sparks


 > Original poster: "john cooper" <tesla-at-tesla-coil-dot-com>
 >
 > Does this enigma basically boil down to timing issues (once we resolve the
 > vernacular)?  And the difficulty in tuning/measuring same throughout the
 > system?  I'm intentionally leaving out the other dozen(s) variables. Jeez,
 > what a can of worms, I only have two storage scopes, that's not enough.
We
 > need an X prize for this one, where's Paul Allen when we need him?  And
all
 > 3 or 4 left standing can applaud.
 >
 > John
 >
 >
 > ---------- Original Message ----------------------------------
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date:  Wed, 23 Jun 2004 21:22:17 -0600
 >
 >  >Original poster: Sean Taylor <sstaylor-at-uiuc.edu>
 >  >
 >  >I've gotta reply to this . . .
 >  >
 >  >On Wed, 23 Jun 2004 11:21:47 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:
 >  >>if you are rating
 >  >>your TC in power units (watts) it does not make engineering sense to
say
 >  >>the efficiency is equal to anything. Efficiency refers to energy units
 > not to
 >  >>power units.  However, if you are rating your TC in power units it does
 >  >>make sense to say it has a power gain of a certain amount. You can then
 >  >>use this number to compare with other TC's.
 >  >
 >  >Giving an efficiency in power makes perfect sense.  Most devices are
rated
 >  >in this way.  A motor has a certain electrical power in, and a certain
 >  >mechanical power output.  The efficiency is defined as Mechanical power
out
 >  >/ electrical power in.  A heater, lightbulb, and many other devices can
be
 >  >given an efficiency rating the same way!  What doesn't make sense is to
say
 >  >we have a motor which has a certain power output, and then try to
calculate
 >  >the energy output by lifting a mass, or some other means and at the same
 >  >time monitoring the input power and integrating - much more of a pain,
and
 >  >will arrive at (approximately, due to measurement error) the same
result.
 >  >
 >  >>The above, of course, does not solve the problem of how to properly
test and
 >  >>rate a Tesla coil when using spark length as the TC output. In the past
only
 >  >>a few coilers could rate and test their coils properly. This resulted
in
 >  >>shorter sparks. However, everyone was more impressed by that random
extra
 >  >>long spark so any tests that gave shorter sparks were not popular.
 >  >>The problem was the true input energy that actually created that
special
 >  >>extra long spark could not be determined so true TC comparisons could
not be
 >  >>made. Only continuous sparking with fixed lengths made sense. But it
does
 >  >>not appear that we will ever get away from that mysterious random extra
long
 >  >>spark test with an unknown input ( except maybe for one shot tests).
 >  >>
 >  >>John Couture
 >  >
 >  >
 >  >What is rating a coil "properly"?  The only way to have a relatively
 >  >constant bang energy is to use a triggered type of gap (rotary, etc.)
and
 >  >then how do you calculate the energy in and out?  What is rated
"properly"
 >  >such that the coil ran with a "constant" length spark?  As line voltage
 >  >fluctuates, and environmental conditions change, so will the spark
length
 >  >on the output, and there is no "rating" that will change that.  I am
 >  >interested to know what you are suggesting changing on a coil that would
 >  >"rate it properly".  Do you have any documented proof that this was
done,
 >  >or what was changed?
 >  >
 >  >In your other post regarding the energy in a single spark, I'm sorry to
 >  >say, but that is complete bull.  There are several problems with the
logic
 >  >- 1) How was the breakrate known to be 120?  2) The system definitely
isn't
 >  >lossless!!!  3) Wattmeters don't give you Watts/sec, just watts, that's
 >  >it!  4) There is streamer growth over successive bangs, so unless you
know
 >  >the voltage you charged the tank gap too, are running ina single shot
type
 >  >of set up, and know the exact losses of the system, there is no way to
know
 >  >the energy in the 8.25" arc!!  As you state, there IS a lot more, but
the
 >  >problem is this isn't even a start towards really figuring anything
 >  >out.  The energy in an arc is not solely determined by its length
either,
 >  >as you can have different amounts of current flowing through the arc,
and
 >  >thus very different amounts of energy.
 >  >
 >  >I'm not trying to insult you, John, but there are several very
fundamental
 >  >mistakes in the calculations you have done (specifically in calculating
 >  >voltage, current, etc. in the secondary), and you should really try to
read
 >  >up on how the quantities interact/relate.  One definite flaw was
"Secondary
 >  >current = joules/voltage".  I'm not going to use more time/bandwidth of
the
 >  >list, and I'm sure several people are getting tired of this discussion,
so
 >  >I'll leave this discussion with this:  True power ratings are a very
good
 >  >estimator of how much power is getting to the actual coil for the same
 >  >type, ie SGTC, SSTC, etc.  To compare Steve's ISSTC to a SGTC with the
same
 >  >power input that gets half of the spark length tells me that either a)
The
 >  >losses in the ISSTC are much lower, or b) the output waveform of ISSTC
is
 >  >such that it is able to facilitate streamer growth to a much greater
extent
 >  >than the SGTC, and for the purposes of the hobby, I would consider
either
 >  >scenario to be much more efficient than the SGTC!
 >  >
 >  >Sean Taylor
 >  >Urbana, IL
 >  >
 >  >
 >  >
 >  >
 >
 >
 >
 >
 >
 >