Description about compensating winding

hi friends, today i want to share about compensating winding which we use to reduce cross-magnetising effect of armature reaction. Before that checkout what armature reaction is and how to reduce the armature reaction.....

Compensating winding:

Compensating winding is a winding which are connected in series with armature and are placed in pole faces.These are used in large direct connected machines which are subjected to large fluctuations in load.

In the absence of compensating winding , the flux will be suddenly shifted backward and forward with every change in load. This shifting will induce statically induced emf in the armature winding.

The magnitude of this emf will depend upon the rapidity of changes in load and amount of change. It may be so high as to strike an arc between the consecutive commutator segments across the mica insulation which may results in flash over of whole armature.

These winding are embedded in slots in the pole shoes and are connected in series to the armature coils in such a way that the current in them flows in opposite direction to that flowing in armature conductors directly below pole shoes

These compensating winding should counter act to the armature mmf so that it should reduce cross magnetizing effect. To reduce the armature effect of cross magnetizing we have to know the quantity of armature mmf. To know the amount of armature mmf we have to know the number of conductors which are cause for cross magnetizing effect.

These compensating winding are connected in series with armature coils so the amount of current passing will be same then we have to calculate number of coils responsible for cross magnetizing effect and same number of coils should be connected as compensating winding in such a way that the armature mmf should be in opposing to compensating mmf.

Now calculate the number of armature coils which are cause for cross magnetizing effect of armature reaction.