In one radio station in which I worked, they had some regulating transformers
that
would give 118 vac out with 95-135 volts in. There were taps to run it off 220,
which
they did, with an input of + or - 20 volts for 230 out. There was one thing that
should
be noted is that they get very warm if running near the rated load. They also
used to
hum a bit.

Leanne