Fwd: [CAD_CAM_EDM_DRO] stepper motor magnetizing
Posted by
Denis Casserly
on 2008-12-15 21:01:21 UTC
Hi all,
here's how one guy did magnetizing.
---------- Forwarded Message ----------
Subject: [CAD_CAM_EDM_DRO] Re: A little experiment on demagnetization
Date: Tuesday 04 February 2003
From: "mayfieldtm <mayfiet@...>" <mayfiet@...>
To: CAD_CAM_EDM_DRO@yahoogroups.com
I designed a couple of magnetizers back in the early 70's.
Different magnetic materials required different equipment.
Alnickel can be magnetized with a very short yet strong
magnetic field, where Ferrites needed multiple longer bursts
of the magnetizing field.
One magnitizer I built was for Alnickel 2" dia. bars approx.
10" long. These would be magnetized while in their
assemblies.
The magnetizer used a bank of 400 volt capacitors with a
total of about 200,000 uF. (If I remember correctly?)
After charging the caps, they would be discharged through
a short piece of double not (00 gauge) stranded copper wire.
The magnet had about three turns of the wire around it.
The discharge switch was an "Ignitron" tube. (I understand
that hockey puck sized "SCR's" have replaced the "Ignitron".)
The Ignitron is a mercury filled vacuum tube that could be
made to act as a full short in microseconds. The currents
involved were extreamly high, yet extreamly short with no
heating.
I've used small table top units with about 27 gauge wire
coils wire on thumb sized Alnickel. Rated at hundreds of
ampers with no heating of the wire!
I'm not convinced that steppers that use Alnickel, can not
be recharged, and more than likely this is probably how the
manufactors do it. If so... someone could cash in on
recharging all these surplus units.
One thing I did learn about "Keepers", removing then slowly
did less damage. Probably true with removing rotors.
Tom M.
Addresses:
FAQ: http://www.ktmarketing.com/faq.html
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OFF Topic POSTS: General Machining
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you have trouble.
http://www.metalworking.com/news_servers.html
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site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
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bill
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-------------------------------------------------------
here's how one guy did magnetizing.
---------- Forwarded Message ----------
Subject: [CAD_CAM_EDM_DRO] Re: A little experiment on demagnetization
Date: Tuesday 04 February 2003
From: "mayfieldtm <mayfiet@...>" <mayfiet@...>
To: CAD_CAM_EDM_DRO@yahoogroups.com
I designed a couple of magnetizers back in the early 70's.
Different magnetic materials required different equipment.
Alnickel can be magnetized with a very short yet strong
magnetic field, where Ferrites needed multiple longer bursts
of the magnetizing field.
One magnitizer I built was for Alnickel 2" dia. bars approx.
10" long. These would be magnetized while in their
assemblies.
The magnetizer used a bank of 400 volt capacitors with a
total of about 200,000 uF. (If I remember correctly?)
After charging the caps, they would be discharged through
a short piece of double not (00 gauge) stranded copper wire.
The magnet had about three turns of the wire around it.
The discharge switch was an "Ignitron" tube. (I understand
that hockey puck sized "SCR's" have replaced the "Ignitron".)
The Ignitron is a mercury filled vacuum tube that could be
made to act as a full short in microseconds. The currents
involved were extreamly high, yet extreamly short with no
heating.
I've used small table top units with about 27 gauge wire
coils wire on thumb sized Alnickel. Rated at hundreds of
ampers with no heating of the wire!
I'm not convinced that steppers that use Alnickel, can not
be recharged, and more than likely this is probably how the
manufactors do it. If so... someone could cash in on
recharging all these surplus units.
One thing I did learn about "Keepers", removing then slowly
did less damage. Probably true with removing rotors.
Tom M.
Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
Moderator: pentam@... indigo_red@... [Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
http://www.metalworking.com/news_servers.html
http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister
site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
-------------------------------------------------------