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Re: SSTC does 10 foot sparks
Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>
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.
----- Original Message -----
From: "Tesla list" <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.
> need an X prize for this one, where's Paul Allen when we need him? And
> 3 or 4 left standing can applaud.
> ---------- 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
> >>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
> >in this way. A motor has a certain electrical power in, and a certain
> >mechanical power output. The efficiency is defined as Mechanical power
> >/ electrical power in. A heater, lightbulb, and many other devices can
> >given an efficiency rating the same way! What doesn't make sense is to
> >we have a motor which has a certain power output, and then try to
> >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,
> >will arrive at (approximately, due to measurement error) the same
> >>The above, of course, does not solve the problem of how to properly
> >>rate a Tesla coil when using spark length as the TC output. In the past
> >>a few coilers could rate and test their coils properly. This resulted
> >>shorter sparks. However, everyone was more impressed by that random
> >>long spark so any tests that gave shorter sparks were not popular.
> >>The problem was the true input energy that actually created that
> >>extra long spark could not be determined so true TC comparisons could
> >>made. Only continuous sparking with fixed lengths made sense. But it
> >>not appear that we will ever get away from that mysterious random extra
> >>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.)
> >then how do you calculate the energy in and out? What is rated
> >such that the coil ran with a "constant" length spark? As line voltage
> >fluctuates, and environmental conditions change, so will the spark
> >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
> >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
> >- 1) How was the breakrate known to be 120? 2) The system definitely
> >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
> >the voltage you charged the tank gap too, are running ina single shot
> >of set up, and know the exact losses of the system, there is no way to
> >the energy in the 8.25" arc!! As you state, there IS a lot more, but
> >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
> >as you can have different amounts of current flowing through the arc,
> >thus very different amounts of energy.
> >I'm not trying to insult you, John, but there are several very
> >mistakes in the calculations you have done (specifically in calculating
> >voltage, current, etc. in the secondary), and you should really try to
> >up on how the quantities interact/relate. One definite flaw was
> >current = joules/voltage". I'm not going to use more time/bandwidth of
> >list, and I'm sure several people are getting tired of this discussion,
> >I'll leave this discussion with this: True power ratings are a very
> >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
> >power input that gets half of the spark length tells me that either a)
> >losses in the ISSTC are much lower, or b) the output waveform of ISSTC
> >such that it is able to facilitate streamer growth to a much greater
> >than the SGTC, and for the purposes of the hobby, I would consider
> >scenario to be much more efficient than the SGTC!
> >Sean Taylor
> >Urbana, IL