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
Arclight has a very good point, with a shitty gap you will get shitty performance. And make sure the strike rail wire is nowhere near the primary. And of course like Ultra said, make sure it's not a shorted turn.
Registered Member #1292
Joined: Wed Feb 06 2008, 04:09AM
Location: Mesa, AZ
Posts: 25
Thanks for the advice everyone. My strike rail is 1 inch short of a full circle - should I cut more out? I'll try changing the spark gap and let you know how it turns out. What kind of gap would you recommend?
Registered Member #1157
Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307
Coronafix wrote ...
Arclight has a very good point, with a shitty gap you will get shitty performance. And make sure the strike rail wire is nowhere near the primary. And of course like Ultra said, make sure it's not a shorted turn.
My first spark gap was an RQ or "Richard Quick" style spark gap. or Very easy to build, and with more electrodes. With a large number of electrodes and a larger discharge surface, it will go longer between cleanings, and give you differing gap widths to choose from. I made mine with six electrodes and ended up adding a seventh to see if the increased gap width would improve the performance. One lead is mounted permanently on the far end electrode, and one has a nice thick alligator clip so that I can clip on to whichever other electrode I want for the effect I want. Worth a try.
There is also the sucker gap that many have come to love as well.
Registered Member #1157
Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307
Zorink wrote ...
Thanks for the advice everyone. My strike rail is 1 inch short of a full circle - should I cut more out? I'll try changing the spark gap and let you know how it turns out. What kind of gap would you recommend?
Id remove another 2 to 3 inches, and then check your performance with that. As for the gaps, see above.
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
Ultra 7 -
As long as the strike rail is not a closed loop, the distance across the gap doesn't matter: 1/10 of an inch, or 10 inches. It's only when its an electrically closed loop that any current can be induced in it from the primary coil's magnetic field.
Zorink -
Very nice looking coil! However, the coil should be capable better performance than you're currently getting.
A few suggestions:
1. Is the black surface that the spark gap is attached to wood? If so, I'd mount the spark gap electrode holders on a piece of insulating material (phenolic, G10, or any other piece of plastic you might have, or use some of the ceramic insulators like you used on your Terry filter to isolate all HV from any wood structure.
2. Double-check the value of all the bleeder resistors used in the Terry filter, and in your MMC; make sure that they are all 10 meg (or higher).
3. You stated that you "tuned" the coil using an oscilloscope & signal generator. Can you describe exactly how you did this? When measuring the resonant frequency of the primary circuit, did you include the length of all the wiring connecting spark gap, MMC, and primary coil?
Registered Member #1292
Joined: Wed Feb 06 2008, 04:09AM
Location: Mesa, AZ
Posts: 25
Herr Zapp wrote ...
A few suggestions:
1. Is the black surface that the spark gap is attached to wood? If so, I'd mount the spark gap electrode holders on a piece of insulating material (phenolic, G10, or any other piece of plastic you might have, or use some of the ceramic insulators like you used on your Terry filter to isolate all HV from any wood structure.
2. Double-check the value of all the bleeder resistors used in the Terry filter, and in your MMC; make sure that they are all 10 meg (or higher).
3. You stated that you "tuned" the coil using an oscilloscope & signal generator. Can you describe exactly how you did this? When measuring the resonant frequency of the primary circuit, did you include the length of all the wiring connecting spark gap, MMC, and primary coil?
1.Yes, the black is wood. I'm going to try the RQ gap that Ultra7 posted so that should get it away from the wood as well.
Registered Member #160
Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938
My first spark gap was a multiple static gap like the Richard one but not inside a tube, worked very well. Next I tried the sucker gap and had increased performance, but the noisy vacuum cleaner is a trade off. Performance was about 10% spark length increase. Just try messing with the tuning, you'll quickly see the difference.
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
Zorink -
Again, when you measured the resonant frequency of the tank circuit, did you include the length of all the wiring between the primary coil, MMC, and spark gap?
A better description of the measurement technique can be found at:
Just short the spark gap, and connect the signal generator across the tank cap. This method automatically includes all the inductance of the actual wiring in the measurement.
Also, you will probably find that "better" initial spark output will be obtained if the resonant frequency of the primary is initially adjusted to 10-12% LESS than the measured resonant frequency of the secondary. This is supposedly because as HV charge accumulates on the toroid, it creates a cloud of ionized air all around the toroid, which increases its effective size, which increases its efffective capacitance, which lowers the actual resonant frequency of the secondary. Basically you are tuning the secondary to the operating frequency of the secondary, not the "static" resonant frequency.
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.
Help! My coil almost works
