Using a 240:32 transformer configured for 272:240, fed on the 272 side with 277 volts nominal, should get about 244.5 volts nominal out on the 240 side. That's 244.5 volts L-N.
272 volts is close enough to 277 volts that I'm assuming the transformer should be OK with it.
How often is this kind of thing done?
I'm just pondering the possibilities for running large numbers of computers directly on 240 volts. This is not a current project or such ... just "armchair thinking".
I'd think 244.5 should be OK with the 100-240 volt computer power supplies. The idea with the autotransformer is how to get close to the 240 volt level with minimal transformers (hence the buck-boost autotransformer) in cases where the utility won't provide anything else between 208/120 and 480/277 (which is probably most of them), such as the ideal 416/240.
Using a 240:48 transformer configured for 288:240 would step 277 volts down to 230 volts. But it would be somewhat less optimal than the previous configuration (5.6% more current on conductors and 50% more transformer capacity).
