Yksifaasisjärjestelmän

Yksifaasisjärjestelmä, meaning "single-phase system" in English, refers to an electrical power distribution system that uses only one alternating voltage waveform. This is in contrast to a three-phase system, which utilizes three waveforms that are offset in time. Single-phase power is commonly found in residential and small commercial buildings for powering everyday appliances and lighting.

The primary characteristic of a single-phase system is its simplicity. It typically consists of two wires: a live or hot wire and a neutral wire. The voltage alternates between these two wires, creating a cycle of electrical current. While simple and cost-effective for lower power demands, single-phase power is less efficient than three-phase power for transmitting large amounts of electricity over long distances or for running heavy machinery.

In a single-phase system, the voltage and current rise and fall together, reaching zero twice during each cycle. This means that the power delivered is not constant, leading to pulsating torque in motors. For many household applications, this fluctuation is not noticeable. However, for industrial applications requiring continuous and high power, a three-phase system is preferred due to its more consistent power delivery and higher efficiency. The generation of single-phase power is usually done by tapping off one phase of a three-phase system.