In a delta-connected transformer, what is the relationship between line and phase voltage?

In a delta-connected transformer, the relationship between line voltage and phase voltage is defined by the geometry of the connections. Specifically, in a delta connection, the line voltage is √3 times the phase voltage. This occurs because each phase of the transformer is connected in a triangular (delta) shape, leading to the following relationship:

• Each line voltage connects to two of the three phases, and the voltage across each phase can be calculated from the phasor diagram of the system. In this arrangement, the line voltage encompasses the total voltage across the two phases connected to the line, which differs from the voltage across just one phase.

Thus, if you take any two lines of a delta-connected transformer, the line voltage can be expressed as the square root of 3 (√3) times the phase voltage. This ratio is crucial for calculations involving power systems, transformer operations, and community electrical installations, providing essential information for accurate design and troubleshooting.

Understanding this relationship is vital for electrical engineers and technicians, ensuring they can effectively work with three-phase systems and transformers in practical applications.