I have acquired a big(4kva) three phase transformer. the primary is a star
configuration and the secondary a single voltage delta. it is wound on three
limbs of an iron core.
I can separate each of the primary and secondary windings to give three
pairs each wound on a limb of the core.
I suspect this is perfectly normal - but I've never looked at one before.
Playing (on paper) with the turns ratios, my application of voltage step up
from 240 to 415 would be satisified by putting each primary in series across
the mains and putting each secondary in series. each winding would get less
voltage than originally designed thus not exceeding the original turns per
volt.

Provided I connect each winding start to finish in the right order, is there
anything to stop me using it in this way?

I've done a bit of a search on three phase transformers but not
surprisingly, I've not found anything about using them for single phase
applications.

I'd be grateful for any info.

regards

Bob

"why is is that I always want to use things for purposes that they were not
designed for??"