Re: Crushing ferrite cores to make one big one?

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Original poster: "Robert Jones" <alwynj48-at-earthlink-dot-net> 

Hi,

I don't think it would make a very good 60Hz transformer core. You would
probably require 10 or more times the number of turns compared to laminated
iron and possible 50 !!! .

However assuming you want to try it read the following.  I have tried to
crush ferrite cores to make a choke core.  The problem is its very difficult
to get a fine powder that will pack well.  I even tried putting  the results
of hammer smashing in a small two pint ball mill with a collection of 1 inch
bal bearing.  After a week or more of tumbling  it did produce a small
quantities (<1/4lb) of fine powder and a lot of smooth irregular ferrite
pebbles.  I also tried an old coffee grinder very effective at producing
very small quantity of powder from small crushed pieces but it rapidly wears
the blades away.  To produce say a few pounds of fine powder would have
required months of tumbling or tens of old coffee grinders.

I think to reduce all the results of smashing the cores to a fine powder in
a ball mill,  requires the balls are much bigger than the biggest pieces
that are required to be crushed.  Say three inch steel balls or quarts
pebbles in a one or two gallon tumbler.

Bob


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, February 14, 2004 11:01 AM
Subject: Crushing ferrite cores to make one big one?


 > Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >
 > I've been on the prowl for cheap transformer cores recently and something
 > just occured to me. I have TONs of ferrite cores, and they are amazingly
 > cheap to obtain in large weight. what If I just took and ground them up,
 > then say filled a 3 inch PVC pipe with them? I could use this as a core
for
 > a fairly large 60 Hz transformer couldnt I? Any thoughts on this somewhat
 > crazy idea?
 >
 >