What is the formula for the phase voltage of a wye winding?

The phase voltage of a wye winding in a three-phase electric system can be derived from the relationship between line voltage and phase voltage in such configurations. In a wye (or star) connection, the line voltage is the voltage measured across two of the three-phase lines, while the phase voltage is the voltage measured across one phase winding and a neutral point.

For a balanced three-phase system, the relationship can be established as follows: the phase voltage is equal to the line voltage divided by the square root of three. This is due to the geometry of the voltages represented in a phasor diagram, where the phase voltages are at 120 degrees apart from one another. Thus, the line voltage is effectively a "resultant" of the vector addition of two phase voltages.

Given this geometrical relationship, the correct formula showcases that while the phase voltages’ magnitudes are related to the line voltage, the line voltage includes components from multiple phases, necessitating the division by the square root of three to isolate the individual phase contribution. Hence, the formula for the phase voltage of a wye winding is accurately represented as phase voltage equals line voltage divided by the square root of three.