🔍 Key Concepts

• Wye (star) connection means one end of each phase winding is tied together at a common neutral point • In a wye-wye transformer, both the primary and secondary sets of three windings each form their own star (wye) with a neutral point • Compare the diagrams to distinguish wye vs delta (triangle) connections on both primary and secondary sides

💭 Think About

• On each figure, trace the top (primary) windings of T1, T2, and T3: do their inner ends all meet at a single common junction that could be a neutral? • Then, look at the bottom (secondary) windings: do they ALSO have one end of each winding joined together at a separate common neutral point? • For any figure that does NOT have both sides forming a star, decide whether it is delta on one side, or a mix like delta-wye or wye-delta, and eliminate it

✅ Before You Answer

• Verify that the primary side has three windings whose one ends are all tied together (classic wye/star junction) and the other ends go to A1, B1, and C1 • Verify that the secondary side has three windings with one end from each all tied together (neutral N2) and the other ends go to A2, B2, and C2 • Eliminate any figure where either side clearly forms a closed triangle (delta) or has fewer than three windings on that side