enkelfase

Enkelfase, in electrical engineering commonly referred to as a single-phase or one-phase system, denotes an electrical power distribution arrangement that uses a single alternating current (AC) phase to supply electrical loads. In contrast to polyphase systems such as three-phase power, enkelfase systems carry power with one sinusoidal voltage waveform.

Typically, single-phase networks supply residential or light commercial power. In many regions the nominal voltage between the live conductor and neutral is around 230 volts with a frequency of 50 Hz, while in others it may be 110–120 volts at 60 Hz. Some installations use split-phase or center-tapped configurations to obtain two voltages from a single transformer, such as 120/240 V in North America. In general, the exact values depend on local standards.

Single-phase is sufficient for small loads like lighting, household appliances, and small motors, but its power transfer capacity increases only with the square of the current, requiring thicker conductors for high loads. For larger power requirements and improved efficiency of motor operation, three-phase systems are preferred.

Key characteristics include a single sinusoidal voltage waveform, straightforward distribution, and lower infrastructure cost for small networks. However, it provides less continuous power for rotating machines and may experience higher losses in longer feeders compared with balanced three-phase systems.

Origin and usage: Single-phase systems were widely deployed in early AC power distribution and remain common for small-scale, low-cost electricity networks. In modern grids, they often coexist with three-phase networks, interfacing via transformers and phase converters.

See also: three-phase power, split phase, electrical distribution.