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Re: Power Transformers



In a message dated 96-11-10 00:56:47 EST, you write:

<< 
 Found your post on making your own inductor quite fascinating.  Would you
 have any further specific suggestions on building a variable inductor, such
 as: if air core does it matter of it is bobbin wound or edge wound.  If iron
 core is necessary, what should the shape of the core be (I seem to recall a
C
 shaped  iron core with an extra hunk of metal in the gap. I also seem to
 recall that the distance of the "extra hunk" in the gap to the rest of the
 core makes a difference in the shunting characteristics and that it needs to
 be adjusted "tuned" for the desired amount of current limiting).  And does
 the core need to be laminated silicon steel core stock or will 1/2 in iron
 bar for the neighborhood hardware store work?
 
 Thanks in advance.
 
  -DavidF- >>

David,

When we were pondering this, there were several good ideas posted.  One was
to use a 3.0" or 4.0" dia pvc pipe to wind the wire on and use another pvc
pipe that just slides inside to make a moveable core out of.  You would need
to fill it with soft iron pieces that are insulated from each other such as
welding rods, coat hanger pieces coated in varnish, laminations from an old
transformer, etc.  You would need to fashion a lead screw arangement to move
the core in and out and hold it in place.

Or you could wind the wire on a pvc pipe and solder on taps to select the
variable positions then fill the inside with soft iron pieces and pot the
inside to hold all the iron in place.

Ed Sonderman