Welcome
Username or Email:

Password:


Missing Code




[ ]
[ ]
Online
  • Guests: 42
  • Members: 0
  • Newest Member: omjtest
  • Most ever online: 396
    Guests: 396, Members: 0 on 12 Jan : 12:51
Members Birthdays:
One birthday today, congrats!
Frog_Qmak (34)


Next birthdays
03/01 mostlymacros (46)
03/02 Staff (31)
03/02 Doubl3 Helix (33)
Contact
If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.


Special Thanks To:
  • Aaron Holmes
  • Aaron Wheeler
  • Adam Horden
  • Alan Scrimgeour
  • Andre
  • Andrew Haynes
  • Anonymous000
  • asabase
  • Austin Weil
  • barney
  • Barry
  • Bert Hickman
  • Bill Kukowski
  • Blitzorn
  • Brandon Paradelas
  • Bruce Bowling
  • BubeeMike
  • Byong Park
  • Cesiumsponge
  • Chris F.
  • Chris Hooper
  • Corey Worthington
  • Derek Woodroffe
  • Dalus
  • Dan Strother
  • Daniel Davis
  • Daniel Uhrenholt
  • datasheetarchive
  • Dave Billington
  • Dave Marshall
  • David F.
  • Dennis Rogers
  • drelectrix
  • Dr. John Gudenas
  • Dr. Spark
  • E.TexasTesla
  • eastvoltresearch
  • Eirik Taylor
  • Erik Dyakov
  • Erlend^SE
  • Finn Hammer
  • Firebug24k
  • GalliumMan
  • Gary Peterson
  • George Slade
  • GhostNull
  • Gordon Mcknight
  • Graham Armitage
  • Grant
  • GreySoul
  • Henry H
  • IamSmooth
  • In memory of Leo Powning
  • Jacob Cash
  • James Howells
  • James Pawson
  • Jeff Greenfield
  • Jeff Thomas
  • Jesse Frost
  • Jim Mitchell
  • jlr134
  • Joe Mastroianni
  • John Forcina
  • John Oberg
  • John Willcutt
  • Jon Newcomb
  • klugesmith
  • Leslie Wright
  • Lutz Hoffman
  • Mads Barnkob
  • Martin King
  • Mats Karlsson
  • Matt Gibson
  • Matthew Guidry
  • mbd
  • Michael D'Angelo
  • Mikkel
  • mileswaldron
  • mister_rf
  • Neil Foster
  • Nick de Smith
  • Nick Soroka
  • nicklenorp
  • Nik
  • Norman Stanley
  • Patrick Coleman
  • Paul Brodie
  • Paul Jordan
  • Paul Montgomery
  • Ped
  • Peter Krogen
  • Peter Terren
  • PhilGood
  • Richard Feldman
  • Robert Bush
  • Royce Bailey
  • Scott Fusare
  • Scott Newman
  • smiffy
  • Stella
  • Steven Busic
  • Steve Conner
  • Steve Jones
  • Steve Ward
  • Sulaiman
  • Thomas Coyle
  • Thomas A. Wallace
  • Thomas W
  • Timo
  • Torch
  • Ulf Jonsson
  • vasil
  • Vaxian
  • vladi mazzilli
  • wastehl
  • Weston
  • William Kim
  • William N.
  • William Stehl
  • Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Forums
4hv.org :: Forums :: Tesla Coils
« Previous topic | Next topic »   

SGTC Waveforms and tuning - please comment

Move Thread LAN_403
rulmismo
Tue Aug 21 2012, 10:12PM Print
rulmismo Registered Member #4187 Joined: Fri Nov 04 2011, 08:08PM
Location: Spain
Posts: 43
Hi,

I got working recently my first coil, a 480VA SGTC that gives maximun 30cm arcs to pointy targets.

http://youtu.be/G0mHsPRLULU

I don´t know if it is properly tuned but it is the better that I could moving primary connection. Frequencies seem to match quite reasonably javatc resullts.
K is about 0.1 and primary N just about 3,4 turns (lead and MMC stray inductance are a little high).

Spark gap is just 1 gap of copper tube with vacuum cleanear sucker type.

I am not sure if it is usual that just two nothes quenches the arc.

Regards and thanks for your feedback!
]tesla_coil_waveforms.pdf[/file]
Back to top
Sigurthr
Wed Aug 22 2012, 01:39AM
Sigurthr Registered Member #4463 Joined: Wed Apr 18 2012, 08:08AM
Location: MI's Upper Peninsula
Posts: 597
The coil appears to be firing at a VERY slow rate, which is usually what happens when the spark gap is too wide. Try adjusting the gap closer until you can't hear each individual "click", you should get better results. As it is now the coil is probably ringing down completely between each firing, which limits streamer growth in SGTCs.
Back to top
rulmismo
Wed Aug 22 2012, 07:54AM
rulmismo Registered Member #4187 Joined: Fri Nov 04 2011, 08:08PM
Location: Spain
Posts: 43
Thanks for the reply.

It is firing every 50ms aprox. see graph,

I will try that, th gap is about 8mm now. I will test in some days and update...

should I get 10ms firing rate to optimise it?
1345622083 4187 FT143656 Firing
Back to top
Sigurthr
Wed Aug 22 2012, 08:40AM
Sigurthr Registered Member #4463 Joined: Wed Apr 18 2012, 08:08AM
Location: MI's Upper Peninsula
Posts: 597
50mS = 20Hz
I knew it sounded off but I didn't think it was that low!

A normal range of firing rates would be about 60Hz to 300Hz. The "ideal" rate for single static spark gap with a "holy grail" NST/MMC combo falls in the 150-200Hz range. So, aim for 175Hz, which is the coil firing every 5.714mS.

Back to top
Steve Conner
Wed Aug 22 2012, 09:55AM
Steve Conner Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I agree, you should make your spark gap smaller before you burn out the NST from overvoltage. frown

A static spark gap charged by an AC supply fires in a chaotic pattern, so it is hard to say what the break rate actually is. But you should definitely aim for an average break rate more like 200 than 20. smile

BTW, are these traces from a Picoscope?
Back to top
rulmismo
Wed Aug 22 2012, 10:40PM
rulmismo Registered Member #4187 Joined: Fri Nov 04 2011, 08:08PM
Location: Spain
Posts: 43
I hope the Terry filter has protected the nst, it wasn´t cheap stuff!

The traces are from a picoscope 3200 with an additional differential probe.

The scope works well, but by experience it is better not use typicial x1 x10 probes if you measure anything>30V. Now I use fixed x10 or differential.

I have no idea of how to take measurements of E field, but following some info about secondary tuning that I found from an old magazine I just used the open leads (10cm apart from each other) in front of the coil. Even without switching on the probe (?) the scope will show the waveforms.

Any of you know where to look for to make a basic E field probe for cheap guys with just an scope? (I guess that some impedance matching to the 1GOhm scope input should be used..).

Regards
Back to top

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob

Go to:

Powered by e107 Forum System
 
Legal Information
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.