RE: Saturable Reactors (yes, again :)) (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 14 Feb 2006 09:58:20 -0800 (PST)
From: J. Aaron Holmes <jaholmes@xxxxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: RE: Saturable Reactors (yes, again :)) (fwd)

Problem is, most pig cores are just one big spool of
metal:

(picture of RTE 15kVA unit out of can)
http://silicon-arcana.com/tesla/rte_guts_small.jpg

But some are sort of like E-I cores because they're
two spools side-by-side:

(picture of Westinghouse 15kVA unit out of can)
http://silicon-arcana.com/tesla/small_westinghouse_guts_1.jpg

The LV side of the pig isn't really center-tapped. 
Rather, there are two completely separate LV windings,
placed in series for 240V (as you can see from the
pictures above).  In 208V Y three-phase applications
where three pigs are used, the LV windings in each pig
are connected together in parallel and one LV bushing
goes unused.

In the case of the RTE above, voltage applied to any
of the windings, LV or HV, will result in voltages on
the other windings (unless you connect the LV windings
parallel opposing, which doesn't seem too useful!), so
your control circuit would have to tolerate this.  Off
hand, I'm not sure what the best way to accomplish
that would be.

With the Westinghouse above, you might be able to cut
some of the windings off, leaving enough of the HV
winding for use as a control winding, and
simultaneously giving yourself room to wind the power
windings around the outer legs.  Or vice versa.

A three-phase transformer seems easier, though.  I
know I can get my hands on a 15kVA one for $50 or so
at my local junk store, but it'll probably have an HV
of only 480 or 600.  Still, it might work.  I'll
probably try it.  If it doesn't work, I've at least
got a boat anchor :)

Aaron, N7OE

--- High Voltage list <hvlist@xxxxxxxxxx> wrote:

> Original poster: Steven Roys <sroys@xxxxxxxxxx>
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Mon, 13 Feb 2006 11:35:28 -0600
> From: Carl Litton <Carl_Litton@xxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: RE: Saturable Reactors (yes, again :))
> (fwd)
> 
> Hi Aaron,
> 
> That does sound interesting.  Please post any
> results on this project.
> We are still working on applications of this
> principle here in our
> group.  We have had some success recently by
> modifying transformers
> removed from x-ray high voltage generators.  
> 
> Since either the control or the power may apparently
> consist of 2
> windings as long a there is no net voltage induced
> into the control, I
> wondered if the transformer removed from a small
> pole pig might also
> work well.  Isn't the low voltage side provided with
> a center tap?  If
> so, it would seem that this might be split into 2 at
> that point and the
> same wired in series opposing so that the net fluxes
> cancel and the HV
> side used as the control.
> 
> Any thoughts on this?
> 
> Carl Litton
> 
> -----Original Message-----
> From: High Voltage list [mailto:hvlist@xxxxxxxxxx] 
> Sent: Monday, February 13, 2006 10:07 AM
> To: hvlist
> Subject: Saturable Reactors (yes, again :)) (fwd)
> 
> Original poster: Steven Roys <sroys@xxxxxxxxxx>
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Sun, 12 Feb 2006 09:55:01 -0800 (PST)
> From: J. Aaron Holmes <jaholmes@xxxxxxxxxxxxxxxxxx>
> To: hvlist@xxxxxxxxxx
> Subject: Saturable Reactors (yes, again :))
> 
> Hi folks, I decided to join the party and try
> building
> one of these.  It seems to me, however, that the
> simplest way to make a big one might be to start
> with
> a ready-made three-phase transformer.  Does that
> seem
> reasonable?  If you're going for a turns ratio
> (control:power) of around 10:1, then a 4160V/240V
> (or
> close) 3PH transformer might be just then thing,
> yes? 
> It would seem like there'd be no winding to do at
> all;
> you'd use the HV winding in the middle for the
> control
> winding, and the LV windings on the outer legs for
> the
> power windings.  You'd have to disconnect the
> windings
> first, since their connections when used as a
> three-phase transformer would obviously be all wrong
> for this application.
> 
> Hmmm...
> 
> Regards,
> Aaron, N7OE
> 
> 
> 
> 
> 
> 
> 
>