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 #1361
Joined: Thu Feb 28 2008, 10:57AM
Location: Cairns, Australia
Posts: 305
Hi, I have made a model of power lines, and want to try simulate what happens when say... a tree branch falls on it. Well it works, when the branch hits it sparks all over the place, but, realy powerlies have fuses. I am trying to make a HV fuse. First i tried laying a small trail of water across some wood, so a couple of seconds after it arcs, the water boils and evaportaes, breaking the circuit. It works well, but the problem is that if the water doesnt evaporate fast enough, the arc forms between the left over puddles of water, and starts burning the wood, which makes a conductive trail of carbon. I tries some thin wire also, but the 15kv 30ma NSt im using doesnt have enough guts to melt it. Anyone have any ideas for a easily resettable, and cheap HV fuse? It doesnt have to be super quick or reliable. The water idea works for the first few times, but then i stops. Something that can be home made.
Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
Doesn't glass become electrically conductive at high temperatures? If it does then as long as the arc doesn't sit there for too long it should be fine.
Registered Member #53
Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638
Glass (and sand) do become conductive when hot enough, I have made fulgerites with both an NST and 4-stack of mots. Maybe ceramic of some kind would work?.
Registered Member #538
Joined: Sun Feb 18 2007, 08:33PM
Location: Finland
Posts: 181
Real powerlines dont have "fuses", they have current and voltage monitoring systems that disconnect faulty lines with breakers (usually a sulfur hexafluoride breaker). I think they even try to automatically reconnect a faulty line after a half a minute or so (atleast from I have seen).
Registered Member #1361
Joined: Thu Feb 28 2008, 10:57AM
Location: Cairns, Australia
Posts: 305
Some of them have sand filled fuses, but i dont want to be spending money buying fuses. I doubt the NST would set them off anyway. Yeah, i have seen some that use monitoring circuits, though i have no idea how id replicate that, since most electronics cant hold up to 15kv.
Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
Make a voltage divider or other voltage sensor on the putput of the NST and use a normal relay to break the input to the NST when the output voltage falls below a certain level. Then you just use a simple switch across the contacs on the relay to restart it.
The voltage sensor can be made in many interesting ways, for example optically using a neon tube/bulb with a series resistor and a fotodiode.
You can also sense the current using a simple coil.
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.
Making a resettable HV fuse?
