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 #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I want to build a simple magnetic levitation device. It will work simple: You have an IR light beam, and feromagnetic object above it. When the object disrupts the light beam, a coil above the object is energized, attracts the object, the coil is deenergized, etc.etc... Looks simple, until it comes to the coil design. How does one determine the right amount of turns, wire gauge, coil shape, core material, core size etc..... ? Also what is the optimal driving voltage and frequency, assuming I will use tl494 to pwm the power switch?
Registered Member #95
Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308
You could check here for starters. and here
When it comes to coil size you want as many turns as possible with as low resistance as possible. Therefor it depends on your coil voltage and the current flowing through it. As far as coil size goes a fatter one should work better than skinny. Frequency will depend on your coils strength and object being levitated. For the driving voltage you want as much current as possible through the coil, so it depends on the coil resistance, but 10 -20 volts is good.
I used 70 meters of 0,45 mm wire for my coil and the resistance was about 8 ohms, which is a little high. My coil gets hot at 12 volts after longer runs.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
ok thanks, I tried to wind a coil (10ohm, about 2x2cm), and it was getting super-hot (thats what I was afraid of) and with iron bolt as core it couldn't lift anything further than about 3mm from the bolt, so I probably need to wind a new monster-sized coil. Or are there any tricks to make it run cooler?
edit> I think I have an idea how to cheat- use a permanent magnet to "help" the coil and put another permanent magnet on the levitated object so they attract each other, now you need much less power to the coil, but I think that stability will be a problem.
edit2> yeah, a permanent magnet on the leitated object greatly increases attraction distance, and the difference between coil-on ond coil-off is still big :)
one more edit : I bought one IR diode and one IR phototransistor. They look the same, except one is clear and the other has gray-green dark tint. Does anybody have an idea which is which ?
Registered Member #51
Joined: Thu Feb 09 2006, 04:17AM
Location:
Posts: 263
A 2x2cm square coil is probably too small, mine is like 4x4cm. I'm not sure what AWG wire you are using, but I used 18 AWG, which is probably too big.
I think stability will be a problem in your design, because your rig will only have two states, right?(On and off) I found that I even needed a lead compensation circuit, and my design is actually feedback based.
As for the IR diode/transistor pair, the one with the dark green tint Should be the transistor. I think they make the epoxy around it a color that filters out visible light so that the transistor only responds to the matching IR LED.
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.
Levitator coil design
: I bought one IR diode and one IR phototransistor. They look the same, except one is clear and the other has gray-green dark tint. Does anybody have an idea which is which 
?
