[jea48]

Its not a transformer, it is a autoformer. Dont use it for hifi, just for your refrigerator.
It offer no protection since it let pass all the tension in/out, it connect your equip to the nearest HV station transformer.

I would never use any transformer at all IMO.

Actually the Signal DU and SU transformers can be configured, wired, as an isolation transformer or as an autotransformer

[jea48]

You can not do it, 60V + 60V are not 120V.
Electricity is not added as oranges (2+2=4)
There is a vectored formula (about 173 if I remember well) to join two different phases.
There is a loss of about 13% in the biphasic that is your case.

 Two single phase secondary windings configured, wired, as a split phase secondary winding.
 http://www.allaboutcircuits.com/textbook/alternating-current/chpt-10/single-phase-power-systems/

[FullRangeMan]

Two single phase secondary windings configured, wired, as a split phase secondary winding.
 http://www.allaboutcircuits.com/textbook/alternating-current/chpt-10/single-phase-power-systems/

I surprised if this combo works as stated, it show zero loss.

[jea48]

I surprised if this combo works as stated, it show zero loss.

What do you mean by zero loss?

[Speedskater]

All power transformers have some loss, that's why they get warm. Poorly designed one get hot.
That page has a lot of unneeded math.

[FullRangeMan]

What do you mean by zero loss?

There is some copper loss(at winding) and some iron loss(at core).

[G Georgopoulos]

excellent frm
may i add power loss effects transformer regulation