The Y-delta transform (also written Wye-delta transform or Kennelly's Delta-Star transformation) or star-mesh transformation is a technique to simplify analysis of an electrical network. The name derives from the shapes of the circuit diagrams, which look respectively like the letter Y and the Greek capital letter Δ.

Basic Y-Delta transformation

The transformation is used to establish equivalence for networks with 3 terminals. Where three elements terminate at one point (node) and none is a source, the node is eliminated by transforming the impedances.

For equivalence, the impedance between any pair of terminals must be the same for both networks.

Transformation equations

Wye-to-Delta transformation equations

Terminology

See also

• Analysis of resistive circuits
• Electrical network: single phase electric power, alternating-current electric power, Three-phase power, polyphase systems
• Electric motors
• Lists: List of transforms, List of mathematical topics

References

William Stevenson, "Elements of Power System Analysis 3rd ed.", McGraw Hill, New York, 1975, ISBN 0070612854