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 #993
Joined: Sun Sept 09 2007, 09:49AM
Location: Southern Finland
Posts: 3
Thanks for clarifying, ZB!
Something started bothering me with this coil energy retrieval thingamajiggy, but i had a hard time remembering what it was... well, i just came by it; if you rectify the surge-back current to take back the energy you use to turn on the magnetic field you will also be taking energy from the moving, magnetized projectile and thus make slow it down, won't you? I tested once by shorting this current out and ended up with 30% less kinetic energy. Of course shorting it out is not exactly the same thing you're talking about, but i have a feeling the power recycling might have a similar effect on the output velocity.
But, the only way to really know your shit is to test it and i do under no circumstances wish to discourage you from trying stuff and learning from it! If you go through with it, please share your results, would be interesting to know.
Registered Member #659
Joined: Fri Apr 20 2007, 09:14AM
Location: SW Hertfordshire, UK
Posts: 75
No, although I am not an expert (yet...). You are only taking back the energy stored by the coil's fairly high inductance, not from the kinetic energy of the projectile.
Actually, a half-bridge configuration tends to increase kinetic energy, as it can create a much sharper fall on the magnetic pulse, reducing any suck-back on the projectile. It can also allow a longer pulse in the first place, allowing more energy to be transferred, and due to the sharper fall, less to be wasted.
This hopefully means more kinetic energy from each stage, and more electrical energy left in the caps after each coil has been fired. Which leaves more energy for later stages, and makes for less recharge time.
Registered Member #993
Joined: Sun Sept 09 2007, 09:49AM
Location: Southern Finland
Posts: 3
Have you tested this claim? i'm fairly certain that when you launch your coilgun the projectile gets magnetized, and due to hysteresis it will not lose it's magnetic field instantly when the coil stops recieving current, so when you use the surge-back to do something you at the same time use the still slightly magnetized projectile as a sort of generator that makes electrical current out of kinetic energy. This is just my theory on why the kinetic energy dropped so drastically when the surge-back was short-circuited..
if i were me i would use a diode-zenerdiode pair to short out only the voltage that goes over the swich transistor's tolerances (especially for MOSFETs) in order to protect it. But then again, that's if i were me! God forbid. Anyway, if you test this, Maruiwlt, please tell me what happened! Is it possible for you to test with and without the rectifier bridge so you could see if the total efficiency changes? I mean, if i'm wrong, it could be an interesting little thing to think about. I also thought about a kind of lame avalanche system, where the coil from the first stage would give its energy to the caps of the second stage and so on.. but than i just kinda forgot about it since it probably wouldn't be worth all the trouble
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.
halfbridge coilgun schematic check
and i do under no circumstances wish to discourage you from trying stuff and learning from it! If you go through with it, please share your results, would be interesting to know.
