PPT Slide
How about this (autotransformer) system?
Section 12.9: Autoransformers
Note that all winding voltages and currents are unchanged*
However, the load’s current has increased (but its voltage hasn’t)
\ |Sload| = |Vload|´|Iload| = 240 V. ´ 687.5 A. = 165 KVA (a 10% increase)
* Ergo, the transformer’s losses are unchanged so efficiency increases
(more output for the same losses)!