This make the use of the fact the a 3 phase delta star transformer boosts the voltage by √3 times and makes the input have to provide √3 times more current. Therefore, 2 sets of 3 phase delta star transformers boost the voltage by 3 times and makes the input provide 3 times as much current. Also, if the three phase power supply has 3rd, 6th, 9th, or some other multiple of three harmonics it will be ignored on the delta end of the delta star transformers, but if it’s on the other side then it acts as a short but only for the multiple of three harmonics.
