480v 3phase to 240 single phase 25kva transformer

[Ktdes423]

Okay I'm going to be wiring a generator with 480v 3 phase to a 100 amp disconnect. Then to a 480/240 v 25kva transformer. Then to a 240 v single phase panel.
My questions are what wire should I use for both sides an how to wire the transformer

 

[templdl]

You could connect the 1ph transformer to two of the 3ph lines of the generator but I don't know how happy the generator will be with an unbalaced load such as this.
There are manufacturers who make 3ph-1ph transformers. The transformers are still not able to balance the 1ph load on all 3 phase though.

 

[hurk27]

I hope this generator is at least a 40kw? as putting a 25kw load on only 2/3rds of the generator will require a much bigger generator then the load, have you looked to see if the alternator can be re-tapped? some 12 leads can be, but with a loss of output?

A 25kw generator will only have the effectiveness of a 16.6kw used in single phase

 

[augie47]

Good advice so far.
Not to be insulting, but with your profile stating "just starting in the field", I would suggest you try and get some hands-on assistance. There are so many angles to a job involving transformers and generators, any advice beyond what has been given, might actually put you on someone else in jeopardy.
You are looking at a job which requires a decent understanding of Art 450 and Art 240 as far as tap rules and transformer secondary conductor rules, and Art 250 as far as proper grounding of your transformer secondary. There are many, many variables that can effect the installation.