Star (Wye) vs Delta Connection

For the same line voltage and phase impedance Z, a delta connection draws 3× the line current and power of a star connection. Star: I_line = V_L ÷ (√3 Z), P = 3·I²·R. Delta: I_line = √3·V_L ÷ Z, P = 3·(V_L ÷ Z)²·R. Star-delta starters use this to cut motor starting current to one third.