What is the voltage across transformer windings when connected wye?

In a wye (or star) connected transformer, the relationship between the line voltage and the winding (or phase) voltage is defined by the geometry of the connection. When the transformer is connected in a wye configuration, the line voltage is equal to the square root of 3 times the phase voltage. Thus, to find the phase voltage, you can take the line voltage and divide it by the square root of 3, which is approximately 1.732.

This means that for a wye connection, the voltage across each winding (phase voltage) is one-third of the total line voltage when considering the geometry of the connection. Therefore, the correct relationship is that the winding voltage equals the line voltage divided by approximately 1.73.

Understanding this relationship is essential for correctly calculating voltage drops, currents, and applying transformer principles in power systems. In contrast, the incorrect options either misrepresent the relationship by suggesting the winding voltage is equal to or directly proportional to the line voltage rather than inversely proportional, which is fundamental to wye connections in three-phase systems.