RE: The "second pig" ballast: Questions.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "david baehr" <dfb25@xxxxxxxxxxx>


I have a book on how to make your own arc welder,.....it states you should 
have 2.5 sq. in. of core for every 1000 watts . I made my own ballast on an 
E I core with a 8 sq. in. center leg area, with 150 turns of #12 high temp 
mag wire. I run up to 3kva, works good,..could go higher I think.Its got a 
range of about 6amps and up.........adjusting the air gap bettween the Es 
and Is

>From: "Tesla list" <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: The "second pig" ballast: Questions.
>Date: Sun, 06 Feb 2005 16:41:31 -0700
>
>Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
>2)  If using the old LV windings sounds like a bad
>idea, about how many turns will I need to rewind the
>core to about 15mH?
>
>Curiously, I see some old posts where people have
>suggested using 200+ turns of wire on an ?EI? core
>with a 16-inch-square center leg.  That seems like an
>awful lot of turns, considering that the LV windings
>on my transformer (with a 24-inch square core) consist
>of only a *few dozen* turns each.  On top of that,
>when I drop 120V across one of the LV windings on an
>almost identical transformer (with the HV side open),
>it only wants about an amp.  So the ?200? figure would
>seem to be off by an order of magnitude?I must be
>missing something, but what is it?
>
>Many thanks,
>Aaron
>
>