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 #325
Joined: Fri Mar 17 2006, 12:42AM
Location: Turku, Finland
Posts: 55
I have two nice, rather large identical stepper motors (unipolar 4 phase permanent magnet). Because I have no information about them I opened one and removed the rotor from the stator to find out how the leads were connected to the windings. I did find out the right stepping sequence to drive them, but apparently opening them was not too smart; being devoid of the metal encasing the rotor seems to have lost some of its magnetic flux . I notice this because the detents when turning the axle are now much less pronounced compared to the unopened one. Also when running it the torque has decreased somewhat.
Is it possible to re-magnetize a demagnetized rotor, using e.g. a Neodynium magnet or an electromagnet? The rotor is a standard two-section toothed rotor and seems to be made up of a large number of stacked iron disks. One end is the north pole and the other end is the south pole. Or will the motor never again see it's original capability?
Registered Member #230
Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284
I thought they put a huge current pulse through the windings after assembly to magntise the rotor. As to which windings and how they connected it I don't know
Registered Member #325
Joined: Fri Mar 17 2006, 12:42AM
Location: Turku, Finland
Posts: 55
Sounds reasonable. Huge current pulses are easy, maybe just putting it through all windings at once could work. The motor is rated for 3 amps per phase in normal use and the windings are about AWG 20-22, any idea of how large current pulse one could use without risk of destroying the windings?
Registered Member #177
Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214
The flux won't come back by this. You permanentley destroyed it, by opening it, making a slightly bigger airgap. This is a well known thing among robotbuilders, and so far no cure is known which can be performed by an amateur.
But on the otherside, most roboteers don't play with high amps like we do, so maybe give it a try.
Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
This got me thinking about how they put together a stepper in the first place. so i googled and got this
scroll down and you will see the remagnetizign station. it can be done, but probably not at home. and i guess you will have to clamp down the shaft, if the stator is multi-pole.
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.