RE: Saturable Reactors as Ballast

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Carl Litton" <Carl_Litton@xxxxxxxxxx>

Thanks for that, Phil.  The diagram is excellent.

Thanks also to everyone who responded on this issue!

Carl Litton



-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Friday, December 23, 2005 1:42 PM
To: tesla@xxxxxxxxxx
Subject: Re: Saturable Reactors as Ballast

Original poster: FIFTYGUY@xxxxxxx

Folks-

     Just like to add that my Miller "Dialarc" welder uses the
Saturable Reactor principle. Instead of transformer taps or a system
to mechanically move a core shunt, a pot on the front adjusts the
control circuit. It has a schematic on the inside cover, but
unfortunately, I can't get to it right now to copy it. But the Miller
website has owner's manuals:

<http://www.millerwelds.com/service/ownersmanuals.php>http://www.millerw
elds.com/service/ownersmanuals.php

I'm pretty sure this is the one for my welder:

<http://www.millerwelds.com/om/o314v_mil.pdf>http://www.millerwelds.com/
om/o314v_mil.pdf

     The schematic shows only one DC control winding, but it may
really be the two out-of-phase windings shown as one. Very simple
arrangement, with the front control dial being a 15W rheostat
directly controlling the DC control voltage. Nice to see everything
first goes through an isolating transformer (with a separate winding
to derive the input to the DC control's rectifier). The Magnetic
Amplifier winding interconnections look a little complex, but there's
also a high/low output switch thrown in there for welder output
ranges. A full-wave bridge on the output for DC welding is obviously
of no use to us (unless you were cascading Magnetic Amplifiers, and
needed that kind of output for the control input to another Amplifier!).
     Another thing I thought of: keeping the DC control circuit's
impedance high makes it easier to filter (if filtering is desirable?).

-Phil LaBudde