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 #200
Joined: Sat Feb 18 2006, 01:49AM
Location: Pskov, Russia
Posts: 21
What shape of the coil is preferable?
This question earlier looked disputable, today like would have mathematics proved answer. Really, there is an optimum form of an electromagnet, with a known ratio of external diameter equal to three internal and length equal to two internal diameters. Such electromagnet creates the strongest magnetic field in the center.
But acceleration of a bullet in an electromagnetic field of the coil is dynamic process. In which time during each moment some parameters of system change at once, first of all a current and position of a bullet. And as the force acting on a bullet, depends both on position, and from a current, the statement about is unique a proper correlation of the sizes of the coil it not seems so obvious any more. Therefore on one of stages of modeling of multistage system I had been formulated a following problem:
There is some conditional stage of the accelerator, approximately in the middle of the barrel, possessing following data:
Diameter of a cylindrical bullet with flat end faces = 6 mm Length of a bullet = 12 mm Length of the coil = 12 mm Internal diameter of the coil = 7 mm. The coil without external iron cover.
The bullet going to the coil with a speed = 55 m/s The coil is connected to the 1000 uF capacitor by a voltage 310V.
The amount of the energy spent by this step is limited, and should be 3,05J. That is, as a result of work of a step, the voltage of the capacitor should decrease from 310V up to 300V.
The step joins at concurrence of a forward end face of a bullet to an end face of the coil and works before full retraction of a bullet. There is instant (we shall examine an ideal case) a switching-off of a current Further.
In this problem it is required to investigate coils with different external diameter, calculations have been for example made for diameters 21, 18, 15, 12, 11, 10, 9 and 8.5 mm.
For each diameter of the coil such diameter of a wire that by the moment of full retraction of a bullet, the voltage of the capacitor has fallen up to 300 Volt, that is the power consumption from the capacitor has made the set 3,05 Joules.
Further it was determined, what of coils of identical length and identical internal diameter, but with various external diameter, will give to a bullet higher speed. Below my calculations generalized results.
So, from the table it is visible, that the greatest efficiency the coil in diameter of 10 mm possesses. And efficiency of the 10-mm coil in 1,66 times above, than at the coil in diameter of 21 mm. Besides of the 10-mm coil the current approximately on 20 % is less, than at 21-millimetric. And one more important plus, the small coil of 10 mm has in six with superfluous time smaller weight, than 21 mm. The total weight of 30 stages these coils will make 160 and 1020 grams accordingly. Excuse for not so pure translation on English. But the basic sense will be clear, I hope.
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.
Modeling of coilgun dynamics