stjärndeltaomvandling

Stjärndeltaomvandling, often referred to as Y-Delta transformation or wye-delta transformation, is a technique used in electrical engineering to simplify analysis of certain electrical circuits. Specifically, it is a method for replacing a network of three components connected in a star (Y) configuration with an equivalent network of three components connected in a delta (Δ) configuration, or vice-versa. The key principle is that the terminal characteristics of the two configurations are identical from the perspective of the three external terminals. This means that the currents flowing into and out of the terminals, and the voltages across the terminals, remain the same for both configurations when connected to an external circuit.

The transformation is particularly useful for analyzing three-phase electrical systems. In such systems, loads or generators can be connected in either a star or delta configuration. When a particular configuration makes the circuit difficult to solve using standard circuit analysis techniques, the Stjärndeltaomvandling can be applied to convert it into the other configuration, often simplifying the calculations significantly. The values of the new resistors in the equivalent configuration are determined by specific formulas that relate the resistances of the original configuration. This allows engineers to analyze complex circuits by breaking them down into more manageable parts.