PhaseSpannung

PhaseSpannung, or phase voltage, is the voltage between a single phase conductor and the reference conductor in a polyphase electrical system, typically the neutral. It is distinct from the line voltage, which is the voltage between two phase conductors.

In three-phase systems there are two common types of conductor connections with different relationships between phase voltage and line voltage. In a star (wye) connection, the phase voltage V_Ph is the voltage between one line and neutral, and the line voltage V_LL is related by V_LL = sqrt(3) × V_Ph. Equivalently, V_Ph = V_LL / sqrt(3). In a delta connection, there is no neutral conductor, and the phase voltage equals the line voltage: V_Ph = V_LL.

Examples help illustrate these relationships. In many European distributions, the line-to-line voltage is 400 V, and the system is star-connected, giving a phase voltage of about 230 V (V_Ph ≈ 400 V / sqrt(3) ≈ 230 V). In a delta-connected system with 400 V line-to-line, the phase voltage would be 400 V.

Phase voltage is important for selecting equipment and insulation ratings. Single-phase loads are typically connected between a phase and neutral (phase-to-neutral), while three-phase loads may be connected line-to-line. Measurement can be done with a voltmeter between a phase and neutral (or ground in grounded systems). Understanding phase voltage helps ensure proper voltage ratings, safety, and compatibility in electrical installations.