Cross-magnetizing effect of armature reaction can be reduced

cross-magnetizing-effect-of-armature-reaction-can-be-reduced

Cross-magnetizing effect of armature reaction can be reduced by __________

A. Removing saturation in teeth and pole-shoe

B. Making smooth pole shoes

C. Chamfering the pole shoes

D. Cannot be determined

I got this question in class test.

I need to ask this question from Ways to Reduce Effects of Armature Reaction topic in chapter Armature Reaction of DC Machines

The correct answer is C. Chamfering the pole shoes

The best explanation: By chamfering the pole-shoes which increases the air-gap at the pole tips. This method increases the reluctance to the path of main flux in a DC machine but its influence on the cross-flux is much greater. This is because the cross flux has to cross the air-gap twice.