Hydro Generator

Mechanically a generator consists of a rotating part and a stationary part

Rotor: The rotating part of an electrical machine.the rotor is a moving component of an electromagnetic system in the electric motor, electric generator, or alternator. Its rotation is due to the interaction between the windings and magnetic fields which produces a torque around the rotor's axis.

Stator: The stator is the stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors or biological rotors. Energy flows through a stator to or from the rotating component of the system. In an electric motor, the stator provides a rotating magnetic field that drives the rotating armature; in a generator, the stator converts the rotating magnetic field to electric current. In fluid powered devices, the stator guides the flow of fluid to or from the rotating part of the system.

The stationary part of an electrical machine, which surrounds the rotor

One of these parts generates a magnetic field, the other has a wire winding in which the changing field induces an electric current
Field winding or field magnets (PMs): The magnetic field producing component of an electrical machine. The magnetic field of the dynamo or alternator can be provided by either wire windings called field coils or permanent magnets. Electrically excited generators includes an excitation system to control the field winding flux. A generator using permanent magnets (PMs) is sometimes called a magneto, or permanent magnet synchronous generators (PMSMs).

Armature: The power-producing component of an electrical machine. In a generator, alternator, or dynamo the armature windings generate the electric current, which provides power to an external circuit.

The armature can be on either the rotor or the stator, depending on the design, with the field coil or magnet on the other part.