Armature Reaction In a DC Generators

A magnetic field is created in the stator by supplying power ( DC power ) to the field winding or using permanent magnets, so create N and S poles in the stator.
We know that flux flows from N to S. At this time the rotating armature cuts the stator magnetic field. As a result current flowing in the armature so the armature flux is created. At this time the armature flux affects the main flux is know as armature reaction.


Some armature conductors carry current in such a direction which causes mmf in opposite direction to that of main mmf. So these conductors cause demagnetising effect and are known as demagnetising conductors.
And remaining conductors carry current in such a direction which causes mmf in the direction perpendicular to that of main mmf, which result in distortion of main field and so these conductors cause cross-magnetising effect and are known as cross-magnetising conductors.