[Big John]

So all the high-side phases are all H1, the neutral is H2, and all the low-side terminals are all dual labeled X1/X2.

Can't wait to see the guys apply their book-learning on the next transformer they get to wire. Apparently apprenticeship courses still leave a lot to be desired.

 

[Big John]

The illustration is showing three single phase transformers connected in wye or delta, not a 3 phase transformer. They connect them in school that way so the students actually make the wye and delta connections and they can see how the voltages add and interact....

Alright, I stand chastened, that's not a terrible idea.

 

[Big John]

Because what they are teaching students isn't exactly real world....

That's why I shot my mouth off when I saw the apparently odd-ball IDs on those terminals, because in my experience this schooling often has a bunch of hypotheticals that will never, ever be applied, and as far as I'm concerned it's a waste of the student's brain-power.

But in fairness, if they're actually letting guys build their own ganged transformers out of little single phase versions, that's actually a really neat way to teach the theory, even if the configurations are unusual.

I've run into and installed more than one ungrounded wye. It would definitely be rare in new construction, but for retrofits and old gear, they're out there.