RE: Saturable Reactors (fwd)

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Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 23 Dec 2005 13:54:07 -0600
From: Godfrey Loudner <ggreen@xxxxxxxx>
To: 'High Voltage list' <hvlist@xxxxxxxxxx>
Subject: RE: Saturable Reactors (fwd)

Hello Carl

I never build a saturable reactor, but
http://www.infodotinc.com/neets/book8/32n.htm may help. 

Godfrey Loudner 

-----Original Message-----
From: High Voltage list [mailto:hvlist@xxxxxxxxxx] 
Sent: Friday, December 23, 2005 10:19 AM
To: hvlist
Subject: Saturable Reactors (fwd)


Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 19 Dec 2005 12:22:46 -0600
From: Carl Litton <Carl_Litton@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Saturable Reactors


Does anyone (Doc, Peter, Jim, etc.) on this list have any experience
building saturable reactors for ballasting purposes?  I found some older
notes in the archive suggesting that a second winding on an iron core
inductor can be used to introduce a variable DC voltage that will give
full range control of the inductance as the core approaches saturation.

I have been able to demonstrate the effect on a small scale with a
simple step down transformer by putting the primary in series with a 120
VAC ciruit and connecting the the secondary to the rectified out put of
a Variac.  A 2.7 Henry inductor  was reduced to a little less than 1
Henry with 140 VDC in the control winding, allowing a small light bulb
just enough current to give off some visible light (measured current
0.188 Amp with no DC control and no light to 0.42 Amp with 140VDC
control and visible soft glow from bulb).

However, all attempts to do this on any large (20 to 250 lbs.) inductors
controlling a 240 volt circuit in the 30 to 150 Amp range have been not
only fruitless but have almost instantly slagged the 25 Amp bridge
rectifier connected to the control winding. 

I need to understand what I am missing here.  Any theory or especially
winding diagrams of working reactors would be greatly appreciated.  I
did find one article that suggested 2 AC power windings in series and in
phase have to be used with 2 DC windings in series and "out of phase"
with each other in order to cancel the effect of induced AC in the
control winding.  But here again, no practical application, turns
ratios, winding configurations, etc.

Any thougts?

Thank you,

Carl Litton

Memphis HV Group