Wye / Delta Line-to-Phase Voltage and Current
The mapping between line and phase (winding) quantities for both three-phase connections: in a wye the line voltage is root-3 times the phase voltage while currents are equal; in a delta the line current is root-3 times the phase current while voltages are equal, with the connection-independent apparent power. The equipment nameplate governs the connection.
Formula and source
Wye: V_line = root-3 x V_phase, I_line = I_phase. Delta: V_line = V_phase, I_line = root-3 x I_phase. Connection-independent S = root-3 x V_line x I_line; P = S x PF. root-3 = 1.73205.
First-principles three-phase winding relations; classical balanced three-phase theory.
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