Sähkögeneraattoria

A sähkögeneraattori, or electric generator, is a device that converts mechanical energy into electrical energy. This conversion is typically achieved through the principle of electromagnetic induction, discovered by Michael Faraday. In essence, a generator consists of a rotor and a stator. The rotor is the rotating part, and the stator is the stationary part. When the rotor, driven by a mechanical source like a turbine (powered by steam, water, wind, or gas) or an engine, spins within a magnetic field, it induces an electric current in conductors present in the stator. Conversely, some generators have a stationary magnetic field and a rotating set of coils.

The fundamental components of most generators include a magnetic field source (either permanent magnets or electromagnets), conductors (usually coils of wire) where the current is induced, and a mechanism for relative motion between the magnetic field and the conductors. The mechanical energy input can come from various sources. For instance, hydroelectric power plants use the force of falling water to spin turbines connected to generators. Wind turbines harness wind energy to rotate their blades and thus the generator's rotor. Thermal power plants utilize steam generated from burning fossil fuels or nuclear reactions to drive turbines.

Generators can produce either direct current (DC) or alternating current (AC). DC generators typically use a commutator to ensure the current flows in one direction. AC generators, on the other hand, produce a current that periodically reverses direction and are far more common for large-scale power generation due to the ease of transforming AC voltage. The output voltage and frequency of an AC generator depend on factors such as the strength of the magnetic field, the speed of rotation, and the number of conductors.