For the production of electricity on a large scale, three phase generators are used.
In power generators, three armature coils are arranged around the field magnet at an angular separation of 120 o .
When the field magnet rotates, three alternating currents of different phases are generated simultaneously in all the three armatures. In each armature, maximum and minimum emfs are generated at different instances. Such generators are three phase generators.
- There are three sets of armature for each field magnet.
- The number of turns in each armature coil is the same.
- The maximum and the minimum value of the induced emf are the same in all the three armature coils.
- The frequency of AC is the same in all the three armature coils.