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*To*: tesla-at-pupman-dot-com*Subject*: Re: SSTC does 10 foot sparks*From*: "Tesla list" <tesla-at-pupman-dot-com>*Date*: Wed, 23 Jun 2004 22:48:01 -0600*Resent-Date*: Wed, 23 Jun 2004 22:51:39 -0600*Resent-From*: tesla-at-pupman-dot-com*Resent-Message-ID*: <IhdCWC.A.SJC.a3l2AB-at-poodle>*Resent-Sender*: tesla-request-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 > > > >

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