Vaihejännitystä

Vaihejännitystä, meaning phase voltage or phase-to-neutral voltage in English, refers to the voltage between one phase conductor of a polyphase electrical system and the neutral conductor. In a three-phase system, this is distinct from phase-to-phase voltage, which is the voltage between any two phase conductors. The relationship between phase voltage and phase-to-phase voltage depends on the configuration of the system, specifically whether it is connected in a wye (star) or delta configuration.

In a wye-connected system, the phase voltage is lower than the phase-to-phase voltage by a factor of the square root of three (approximately 1.732). This is because the neutral point is created by connecting one end of each phase winding together. The phase-to-phase voltage is then the vector difference between two phase voltages. Conversely, in a delta-connected system, there is no neutral conductor, and therefore no defined vaihejännitystä. In such systems, only phase-to-phase voltage is relevant.

Understanding vaihejännitystä is crucial for selecting appropriate electrical equipment, such as motors and transformers, as they are often rated for specific phase voltages. Incorrect voltage ratings can lead to equipment damage or inefficient operation. The neutral conductor, when present, typically carries current only under unbalanced load conditions.