kolmevaihejärjestelmään

The kolmevaihejärjestelmän, or three-phase system, is a method of providing and distributing alternating current (AC) electrical power. It consists of three separate AC currents that are out of phase with each other by 120 degrees. This means that at any given moment, the instantaneous power delivered by the three phases is constant, unlike a single-phase system where the power fluctuates.

This constant power delivery makes three-phase systems highly efficient for generating and transmitting electricity over long distances. It also allows for simpler and more compact designs for electric motors, which are commonly used in industrial and commercial applications. Three-phase power is typically generated by a three-phase alternator, where three separate coils are wound around a rotating magnetic field. The output from these coils is then fed into a distribution network.

In a three-phase system, there are usually three live wires and sometimes a neutral wire. The voltage between any two live wires (line voltage) is higher than the voltage between a live wire and the neutral (phase voltage). This system is the backbone of most modern electrical grids, powering everything from large factories to residential buildings. Its advantages in terms of efficiency, power delivery, and motor performance make it the standard for high-power applications.