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.
Just the usual monkey design: cap-switch-coil, and a diode antiparallel to the cap. The difference is a few turns of wire over the coil, touched by a little cap charged to HV, and sparker as a switch.
Discharge can't be stopped, right - sparker acts just like a thyristor: once become conductive, stays conductive until current stops.
Here is the diagram of the circuit shown in the video above:
The main cap was 60uF x 800V charged to ~770V, resistor was actually 3pc x 1MOhm in series, little cap is 0.1uF x 1000V, diode - 10A07.
Should work the same well for common 400V setups, howhether I would recommend HV applications.
I have just calculated the efficiency of my spark switch. I disconnected cap from charger, removed antiparallel diode and triggered the switch. As a result I got a pure RLC circuit. Voltage on cap inverted from +740V to -240V after the shot. Strange, I expected bidirectional conductance, but anyway, this way is even better... So I charged the cap again, but this time I touched sparker's terminals by a diode. This is equivalent to a mechanical switch with diode in series. This time I got -500V in return. I repeated experiments few times and got closely the same results. Now, neglecting mechanical switch losses and diode Vdrop losses, I'm able to calculate how much energy was dissipated by a spark. So for initial 16.4J stored in the cap I got 5.8J dissipated by the spark switch. Well, almost a third of energy... Howhether I must mention that electrodes are covered by black crap already and made of some iron alloy - so the actual plasma discharge dissipation is just a part of those 5.8J. Anyway, I believe that if this device will be made properly, it may be a way more efficient (not as much as brand-new mechanical switch, of course, and far less efficient than SCR), but what is more important is it kinda unbreakable and have a high current capability, and I expect linear increase in losses relative to current, like in a semiconductor device (SCR), which is an expensive alternative.
Hm, made spark discharger with copper electrodes - the same efficiency. Well, that means that all those 5.8J are actually dissipated by the spark - light emission and electrodes' tips melting. Actually, copper electrodes are not that good - I can see copper "pimples" growing in a place where discharge happens. This changes the air gap gradually.
Oh, and BTW, even with 240V in cap switching works very well, so for conventional 400V setup spark switch will work fine - proved.
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.
Switching Device for Coilgun
