(Slow followup…) Paul, probably the most popular dry-type transformer in the US is 480∆-208Y/120 volts in the range of 15-300 kVA. {In Canada…600∆-208Y/120 volt ratings are common.} The high side is usually served from a utility-furnished 480Y/277 volts (…600Y/346V to the north.) The ANSI standard is a 30° lagging secondary with respect to primary. I think that corresponds to IEC Dyn1 designation. It is also common for the primary to have bolted tap connections, allowing up to six 2½ adjustments in voltage ratio without load-current derating.

There have been limited use of wye autotransformers—480Y/277 to 208Y120 volts, but apparently with all the negative press about triplen harmonics, they really don’t seem to be very popular, even though they can be lighter and lower cost. There is no inherent phase shift high- to low-side.

Under 15kVA 3ø, ‘stock’ transformers are 3, 6 and 9 kVA with ‘480∆-208Y/120V’ ratings, but are typically T-T connected as opposed to true ∆-Y. Again, no inherent phase shift high- to low-side.