A generator or dynamo works on the principle:

Explanation

Electric Generators or Dynamos. Electric generators are devices used to produce electric current. They convert mechanical energy into electric energy. The direction of the current produced in dynamos is in accordance with Fleming.s right hand rule has already been described.
Principle of Electric Generators. Electric generators are based upon the principle of electromagnetic induction. When a coil is moved in the magnetic field, then the current is induced in the conductor or the coil. In dynamos, a rectangular coil having straight sides is made to rotate rapidly in the magnetic field between the poles of a horse-shoe magnet. These days, we use electromegnets instead of permanent magnets. When the coil rotates, it cuts the magnets lines of force due to which a current is produced in dynamo coil.