Ignoramus20688 wrote:


It is a multitap thing that allows buck/boost adjustments of a few
percent. It has various taps that I could use if, say, I have 490
volts input and want 240v output.

My first question is, am I correct in assuming that I could use it in
reverse to get 460v from 240, at some reduced kVa. Also, what is the
realistic kVa number I could get from it.

So, my thinking goes, to make it into a 240-460 transformer, I should
allow for some losses and wire it according to the diagram connection
for 480 volts. Then under load, and due to losses, the voltage would
drop a little to 460. Right?

The bonus question is whether this thing could power a 10 HP motor to
make three phase 460v.

Hi Iggy;

Buck boosts run fine either way, "Buck only" won't. Look for a "270 or
277" voltage among the outputs. If it's there, there is a good chance
that the high voltage winding has a tap for 277 common with the
enclosure and introducing power through the low volt windings will cause
a dead short.

If it does have a 277 tap you'll need to cut the internal wires that
attach to the case (sometimes as many as 4) and ground only on the input
or just run it ungrounded (lots of folks do).

Matt