Adding 480V to Building

The best way would be to get a separate 480V service from the utility. It is also possible to step the existing service voltage up to 480V; but you need a transformer designed for that, not one intended to step down from 480V. The difference will be which winding is wye and which is delta.

You’ll find 480V delta is really easy to find. But that would be wrong for this application. You need a wye on the 480 side and a delta on the source side. Probably a special order.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

It depends.
If your building has three phase power now.
In addition to David's good advice, the choice will be influenced by the 480 Volt load.
For small loads, a step-up or auto-transformer will be the best choice.
You may have to have a transformer custom wound for 277 Volts.
YOU MUST NOT USE A CLOSED DELTA SECONDARY CONNECTION.
One solution for small loads may be an open delta Auto-transformer bank.
You may use two off the shelf 120/240V to 240/480V transformers in an open delta auto-transformer connection.
Your 480 Volt circuit will be corner grounded.
For large loads you may need a second 480 Volt service.

Itsmoked may have posted while I am typing.
This is his specialty.
Another alternative for small three phase motor loads is a single phase Variable Frequency Drive (VFD).
This is great for motors but may not be suitable for some other three phase loads.
Control circuits may need special consideration.
Your existing service must have enough spare capacity for the new loads in any event.
More details about your existing installation and your proposed new machines will result in better answers.


Bill
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"Why not the best?"
Jimmy Carter