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Re: Power Transformers



In a message dated 96-11-09 03:01:35 EST, you write:

<snip>

<< With a 2 kva transformer, you shouldn't need anything as
 large as an arc welder although it should work ok if you have one.  We were
 talking about building a variable inductor at one time and think we decided
 on a range of 5 to 25 mh as the appropriate size - and of course the
 conductors need to be able to carry the full primary current easily.  Your
 transformer at 2kva will draw about 9 amps from the 220 volt line.  You
 should be able to push this to 4 kva or about 20 amps for short periods
 without hurting it at all.  If you don't have access to a welder, you
 probably need to wind an inductor in the 10 to 20 mh range with variable
taps
 to select the current range you want. >>

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-