On Tue, 25 Nov 2003 22:14:36 GMT, "Doug K7ABX"
wrote (with possible editing):

I also have used the regulating transformers at large commercial on shore
radio/computer installations. Sola was the brand we used, one on each leg of
3 phase shore power. Some critical units had small single phase
transformers mounted in the rack. They covered about 95-135 volts in for
constant output. However, they take several cycles of power change for the
change to be seen at the output. I got into trouble having a large UPS unit
feeding the transformers, as the transformer change was slower than the UPS
and we got into a voltage bucking problem. Ended up taking the transformers
out and just using the UPS. Do a web search for Sola line regulator
transformers (they are really a mag amp autotransformer device). E-bay has
them from time to time.

Doug K7ABX

I think there are two kinds. One type uses a swinging core in the
transformer and works by adjusting the output voltage. The other uses
what is known as a "ferroresonant" transformer which works by
saturating the core at resonance with a non-polarized capacitor which
keeps the output steady regardless of input voltage swings. In a
marine environment, I'd opt for the latter as there are no moving
parts.
--

Larry
Email to rapp at lmr dot com