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.
Registered Member #160
Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938
Because the current and voltage are out of phase, the standing waves create a peak current at the base and a peak voltage at the top. Hence the lightning out the top. :)
Registered Member #160
Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938
Unless you are pumping a lot of power into a small coil, the currents in the secondary are still relatively small. Consider a 900VA coil with 200,000 volts on the top load, the secondary would have 4.5mA at the base. Hardly worth the thicker wire at the bottom. Even if it was only 20,000 there would only be 45mA.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Coronafix, your calculations are probably wrong because you forgot to take into account the Q factor of the secondary, and the peak-to-RMS ratio of the output voltage waveform.
If I were you, I'd take that 200kV, divide by the surge impedance of the secondary coil, and then multiply by 0.5 times the square root of (ringdown time * breaks per second) :P
Registered Member #1083
Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256
I've heard that a coil would be ideal if the wire used got gradually thinner as it approached the top and thicker as it neared the base. Of course wire like that simply doesn't exist in a contiuous strand, and seems impractical.
Registered Member #1232
Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881
For what it's worth, about 8 years ago I wound a TC-secondary with 3 different guages or wire to test out this theory.
The bottom 1/5th was wound with 0.7mm, the next 2/5ths were wound with something like 0.45mm and the remaining top 2/5ths were wound with 0.315 I think.
It was thoroughly tested in a conventional (spark gap) Tesla Coil arrangement running at around 1500W. From what I could tell the coil suffered because the thicker wire at the base meant there was less turns in the tightly coupled region close to the primary. It actually worked better when I turned it upside down and ran it with the fine wire at the bottom!
Finally, rewinding the whole secondary with 1500 turns of 0.275mm wire gave better results still.
I personally believe it is coupling and inductance that determine secondary winding performance. It just so happens that 1000-1500 turns gives a suitably high inductance for the typical size of coil most hobbyists make. If G. Leyh's Electrum project had had 1500 turns the Fres would probably have sunk into the dirt!
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.
To short secondary coil, can I use it for anything?
