Re: SSTC does 10 foot sparks

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

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
 >
 >
 >
 >