Transformer spec/wiring question

[rookie4now]

We are stepping up a 120/208 service to 480v. My boss ordered the transformer before going on vacation. The transformer arrived and is specified as "208 Delta Primary - Secondary 480/277."

I know the service has no high leg...ie. all phase to phase and phase to ground voltages are the same. So I'm thinking the primary is wye not Delta. Does it matter that the transformer says Delta primary? We're only going to run a 3-phase motor that shouldn't care if it's delta or wye.

I don't want to call the boos on vacation and tell him the transformer needs to go back if it's ok.

Also, if anyone has some good links in where I can read up on this, I would appreciate it.

Thanks.

 

[kwired]

Primary is wound and connected in a delta configuration, has little to do with the configuration of the source. All that matters is that the input voltage is correct.

Delta connected primary windings is common in transformers of pretty much any voltage or KVA regardless of what the supply is derived from.

 

[LarryFine]

To add, even if the transformer had a primary neutral, you should still leave that terminal floating; not bonded, grounded, neutral'ed, nothing; as if it were a Delta load.

The Delta primary is the correct way to go in almost every installation.

Do not forget that the secondary neutral should be bonded and have a grounding electrode system, unless there's a very good reason not to, and ground-detection equipment has been added.