A generator set is a device that converts other forms of energy into electrical energy, and its basic principle is mainly based on the law of electromagnetic induction.

Taking a common diesel generator set as an example, the thermal energy generated by diesel combustion drives the piston to make reciprocating motion in the cylinder, causing the crankshaft to rotate. This process first converts the chemical energy of diesel into mechanical energy. The rotation of the crankshaft drives the rotor of the generator to rotate, which is usually composed of two parts: the stator and the rotor. When the rotor rotates inside the stator, the magnetic field of the rotor will constantly change with the rotation of the rotor. According to the law of electromagnetic induction, when a part of the conductor in a closed circuit cuts the magnetic induction line in a magnetic field, an induced electromotive force will be generated in the conductor. In a generator, the stator winding is such a closed circuit. When the rotor magnetic field cuts the stator winding, an induced electromotive force is generated in the stator winding, thereby forming a current. If the external circuit is closed, there will be power output.

Looking at wind turbines again, the kinetic energy of the wind drives the blades of the wind turbine to rotate, and the blades drive the rotor of the generator to rotate. Like a diesel generator, when the rotor rotates in the stator, its magnetic field changes cause the stator winding to generate induced electromotive force, which in turn generates electrical energy. However, its initial energy source is the kinetic energy of wind, not the chemical energy of fuel.

For hydroelectric generators, the potential or kinetic energy of water causes the turbine wheel to rotate. The wheel is connected to the rotor of the generator through a shaft, driving the rotor to rotate in the stator. According to the principle of electromagnetic induction, the stator winding generates induced electromotive force, achieving the conversion of mechanical energy from water to electrical energy.

Solar power generators are slightly different, mainly based on the photoelectric effect. Solar cells (photovoltaic cells) are made of semiconductor materials. When photons are irradiated onto the cell, the energy of the photons causes electrons in the semiconductor to undergo transitions, producing electron hole pairs. Under the action of the electric field inside the battery, electrons and holes move towards the two poles of the battery, forming a potential difference. When the external circuit is connected, there is current passing through, achieving the conversion of light energy into electrical energy. In short, although different types of generator sets have different initial energy sources, they are ultimately converted into mechanical energy through appropriate means, and then generate electrical energy using the law of electromagnetic induction (photovoltaic generator sets utilize the photoelectric effect).