Kolmivaiheisen

Kolmivaiheisen, meaning "three-phase" in Finnish, refers to a system that utilizes three separate alternating current (AC) power lines. These lines are typically synchronized but out of phase with each other, usually by 120 degrees. This three-phase system is the dominant method of electric power generation, transmission, and distribution worldwide due to its efficiency and versatility.

The primary advantage of a three-phase system over a single-phase system is its ability to deliver more power with less conductor material. This is because the power delivery in a three-phase system is more constant and smoother, reducing voltage fluctuations and mechanical vibrations in motors. Three-phase power is particularly well-suited for running large electric motors, as they are inherently simpler, more efficient, and have a higher starting torque when powered by three-phase AC.

In a three-phase system, the three conductors carry alternating currents that are offset in time. This phasing allows for a continuous flow of power, unlike single-phase systems where the power drops to zero twice during each cycle. The generation of three-phase power typically occurs in alternators with three sets of windings, spaced 120 electrical degrees apart. The transmission of this power over long distances is more efficient than single-phase at the same voltage level. At the point of use, three-phase power is distributed to industrial facilities, commercial buildings, and sometimes to residential areas with high power demands. For many household appliances and lighting, a single-phase supply is sufficient and derived from the three-phase distribution network.