8.2 : 三相電圧の生成

A three-phase AC generator with a rotating magnet surrounded by stationary windings is used to generate three-phase voltages.

The stator houses three separate coils or windings, with their terminals placed 120 degrees apart.

As the rotor spins, its magnetic field intersects with the coils, inducing equal-magnitude voltages, each with a phase difference of 120 degrees.

Each coil acts as a single-phase generator, enabling the three-phase generator to power both single-phase and three-phase loads.

A three-phase system has three voltage sources connected to loads via three or four transmission lines. These sources can be configured in either a Y or delta connection.

For Y-connected voltage sources with the same amplitude and frequency and a phase difference of 120 degrees, the voltages between lines a, b, c, and the neutral line are the phase voltages, which are balanced, have equal magnitude, and are out of phase by 120 degrees.

In a wind turbine, the rotating blades drive the generator's rotor, inducing a three-phase voltage in the stator coils, which is then transformed and transmitted to the grid.