🔍 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