What device converts mechanical energy into electrical energy using electromagnetic induction?

An electric generator converts mechanical energy into electrical energy using electromagnetic induction.

In a typical generator, a rotor or other conductor moves through a magnetic field. This motion changes the magnetic flux through coils and induces an electromotive force, producing current when the circuit is closed. The mechanical input may come from a steam turbine, water turbine, wind turbine, engine, or hand crank.

Generators and motors are closely related machines. A motor uses electrical energy to create mechanical motion, while a generator runs the energy conversion in the opposite direction. Both rely on magnetic fields and forces on current-carrying conductors.

Large power-station generators commonly produce alternating current because rotating magnetic fields naturally create periodically reversing voltages. A generator does not create energy from nothing: it converts energy supplied by its mechanical drive, with some losses appearing as heat, sound, and friction.