A Δ-Y (3ø4w) transformer is a type of three-phase electric power transformer design that employs Δ-connected windings on its primary and Υ connected windings on its secondary. A neutral wire can be provided on Y output side.
Δ-Υ transformers are common in commercial, industrial, and high-density residential locations, to supply three-phase distribution systems.
The Δ winding allows third-harmonic currents to circulate within the transformer, and prevents third-harmonic currents from flowing in the supply line.
In this case, the voltages are as follows:
Between phases 480V;
Between phases and neutral 277V.
Flip on the SPST switches to turn on primary high voltage.
Switch between the voltmeters to see the different voltages.
