Re: A little experiment on demagnetization

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.