polyphasejärjestelmän

A polyphase system is an electrical power system that uses multiple alternating currents (AC) that are out of phase with each other. The most common type of polyphase system is the three-phase system, which uses three currents that are 120 degrees out of phase. Other polyphase systems, such as two-phase or four-phase, exist but are less common.

Polyphase systems offer several advantages over single-phase systems. They can deliver more power for the same amount of conductor material, making them more efficient for power transmission. They also provide a smoother flow of power, which is beneficial for motors and other inductive loads. Three-phase systems are particularly well-suited for industrial applications and large-scale power distribution due to their balanced power delivery and ability to easily start and run electric motors.

The generation of polyphase power typically involves a generator with multiple windings. These windings are arranged so that the electromotive force (EMF) produced in each winding is displaced in time relative to the others. In a three-phase system, the generator has three sets of windings, each producing an AC voltage that is one-third of a cycle (120 degrees) out of phase with the others. This creates a rotating magnetic field within the generator, which is fundamental to its operation.

Distribution of polyphase power uses transformers to step voltages up for transmission and then down for use by consumers. The configurations of the windings in both generators and loads can be either star (or wye) connected or delta connected, each offering different characteristics in terms of voltage and current relationships. Polyphase systems are the backbone of modern electrical grids worldwide.