The magnet creates a fixed magnetic field in the generator. The coils of the generator move in the magnetic field, and the coils cut the magnetic field to generate electricity. This is electromagnetic induction.

There are many types of generators, all of which operate on the principle of electromagnetic induction.

Generators with permanent magnets are called permanent magnet generators.

When a wire moves in a permanent magnetic field, if the wire is perpendicular to or nearly perpendicular to the magnetic field lines, it will cut the magnetic field lines, and the electric potential difference will occur at both ends of the wire; If a wire forms a closed circuit, when one part of the wire moves in a magnetic field to cut the field line, the wire will generate an electromotive force and thus a current. This phenomenon is called electromagnetic induction, and the current generated is called induced current.

Not all generators have magnets.

If you set up a coil in a generator, and make current flow in the coil, will also produce a magnetic field, this phenomenon is electromagnetic induction.

A generator that uses current through a coil instead of a magnet to generate a magnetic field is called an excitation generator.

The generator's coil moves in this field and cuts the lines of force, which also generates electricity.

Conversely, the generator's generating coils are fixed (called the stator), while the magnet or exciting coil is moving (called the rotor), and its magnetic field lines are cut by the coil to generate current.