480/480 Xfmr?

[follybeacher]

We're tapping and extending from the secondary from these existing xfmrs so it's not imperative I figure it out, but I want to know why there's a 480/480 transformer. Is it because of distance (of which appears far diagrammatically via several hand holes). It doesn't appear they're using a neutral on the secondary side so not because they needed a wye... thoughts?

eta for clarity, the question is: under what circumstance would you use a transformer of the same voltage and how would one size and specify?

 

[charlie b]

I have seen it used as a means of isolating the upstream and downstream distribution systems from each other. You size the transformer for the calculated load, just like for any other transformer. You specify a 1:1 turns ratio, and include whether the primary and secondary are to be connected WYE or DELTA.

 

[ptonsparky]

Would this be a method to reduce the available fault current?

 

[Besoeker]

Would this be a method to reduce the available fault current?

Could be. Chokes would be cheaper.

 

[MAC702]

If the xformer has a few taps for minor voltage differences, it could be used to account for voltage drop. It's nominally a 480/480, but might be hooked up to restore a 5% - 10% voltage drop.

As mentioned, it could also be used as an isolation transformer.