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*To*: tesla@xxxxxxxxxx*Subject*: Racing Arcs Explained???*From*: "Tesla list" <tesla@xxxxxxxxxx>*Date*: Mon, 14 Aug 2006 17:56:41 -0600*Cc*: dest <dest@xxxxxxxxxxx>*Delivered-to*: testla@xxxxxxxxxx*Delivered-to*: tesla@xxxxxxxxxx*Old-return-path*: <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>*Resent-date*: Mon, 14 Aug 2006 19:29:44 -0600 (MDT)*Resent-from*: tesla@xxxxxxxxxx*Resent-message-id*: <i1K_wk_M6-P.A.NtH.IOS4EB@chip1>*Resent-sender*: tesla-request@xxxxxxxxxx

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx> Hi, Just to follow up... If we take the example Dest gave: http://www.pupman.com/listarchives/2006/May/msg00381.html

Primary

Secondary - 28 inches long, 1500 turns, 7 inches diameter. 0.015 wire. Firing voltage 20kV.

http://drsstc.com/~sisg/files/RaceArc-01.gif 91.67kHz and the primary is 39.462uH with a coupling of 0.306...

V2 = M x di(Lp)/dt

http://drsstc.com/~sisg/files/RACEARC4.TXT So we know the mutual inductance of each little section now... To find di/dt we know Ip is in the first instant of firing: I(t) = Vfire x SQRT(Cp / Lp) x SIN (t / SQRT(Cp x Lp)) If we take the derivative: dI(t)/dt = Vfire x SQRT(Cp / Lp) x 1 / SQRT(Cp x Lp) x COS(t / SQRT( Cp x LP)) If t ~~= 0 and with some simplification we get: dI(t)/dt = Vfire / Lp == 20000 / 39.462uH == 507e6 A/S Now we can get out the spreadsheet and make some numbers: http://drsstc.com/~sisg/files/RaceArc6.csv and we can make pretty graphs: http://drsstc.com/~sisg/files/Voltage-length.gif http://drsstc.com/~sisg/files/VoltageEveryInch.gif

http://hot-streamer.com/TeslaCoils/Misc/SGapVolt.jpg

The voltage profiles Paul has at: http://www.abelian.demon.co.uk/tssp/pn040502/ Will enter into this all too... Of course, Gerry's paper provided the key to it all ;-))) http://hot-streamer.com/temp/GerryReynolds/In_search_of_a_better_primary.pdf I CC'ed dest too incase he has comments... Cheers, Terry

Hi, Dest also looked into this: http://www.pupman.com/listarchives/2006/May/msg00387.htmlBut I don't think he did it quite right... The links are dead so Ican't check now. But I think he did the di/dt wrong. If it wasdone right, I think his conclusion would be different ;-)))I have seen miss-tuned coils do some very strange things. Fat 1foot arcs from the lower six inches of the secondary to theprimary... Primary to secondary arcs blowing holes though 1/4 inchG-10... And of course racing arcs... I think all this will beexplained in a few days now :-))))))Cheers, Terry At 10:17 PM 8/13/2006, you wrote:Hi Terry,Yes, I think I have enough info to compute the initial voltageprofile. It will be interesting to also add the wave propagationto the model to see what happens over time and subsequent halfcycles. My guess is that the problem is more complex than theinitial voltage profile but modeling the secondary into managablenumber of segments may be a reasonable way to shed somelight. Maybe we can share ideas on this and the modeling and I canproceed. You have a very intuitive perspective.Gerry R.Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx> Hi Gerry, You may be able to resolve the racing arc issue now. You know the di/dt of the primary coil. You know the coupling to any arbitrary ring along the secondary. You know the inductances.You have a well known coil situation that is apparently close tothe edge to study.If we assume the racing arc occurs in say the first 1/4 cycle(probably in the first micro second!), then the other resonancesand harmonics have no effect since they have not had time to setup yet.Thus, the voltage gradient along the secondary in the firstinstant of firing is now taking into full account the primary tosecondary geometry and coupling...MandK can be set up to find the data in a single run and you canmodify the MANDK.INI file for further control. You can just makethe high increment the same as you coil section increment tocalculate the right data directly.http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.ZIP http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.PDFThe coupling/length output data file can probably be imported to aspreadsheet.Thus, you should be able to graph the Voltage/UnitLength along thesecondary for any primary to secondary configuration in the firstinstant the gap fires and from there determine if that is causingthe racing arcs.If one cleans the gaps, the initial di/dt in the primary coil myincrease. Thus your gap cleaning may indeed have increased thechange for secondary racing arcs.I have always felt that the racing arc issue was a matter of puretransformer action. So maybe you can prove me right :DCheers, Terry At 11:53 PM 8/9/2006, you wrote:Hi All,Terry just put a writeup I did on my investigations using JavaTCinto what may be a better primary concept. It is located at:<http://hot-streamer.com/temp/GerryReynolds/In_search_of_a_better_primary.pdf>http://hot-streamer.com/temp/GerryReynolds/In_search_of_a_better_primary.pdfIf the idea works out, it may allow for higher coupling withoutinducing racing arcs.Please feel free to comment or criticize (hopefulllyconstructively) and If anyone is willing to try the idea, I wouldbe willing to consult.Gerry R

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