What is the difference between an alternator and a generator?

     An alternator is a device that converts mechanical energy into AC electrical energy. A generator is a mechanical device that converts mechanical energy to either AC or DC electrical energy. An alternator always induces an alternating current. A generator can generate either alternating or direct current.

     The alternator has a rotating magnetic field, whereas the generator has a rotating magnetic field for the high voltage generation and a low-voltage stationary magnetic field is used. The alternator does not charge the completely dead battery whereas the generator charges the dead battery.

     The alternator takes input supply from the stator whereas the generator takes input supply from the rotor. Alternators are mainly used in the automobile industry as a charging system for the battery. Generators are widely used to produce large-scale electricity.

     The output EMF of the alternator is variable, and the output voltage of the generator is constant. The armature of an alternator is stationary, and in the case of the generator, it is rotating. The alternator is smaller in size and requires less space whereas the generator requires a large space.

     The Alternator has a wide range of RPM (Rotations Per Minute). The generator has a low range of RPM. The output of the alternator is higher than that of the generator. The output voltage of the Alternator is always higher than Generator. The output voltage of the Generator is always higher than Alternator.