Q.

Commutation in a dc machine may be explained as a process 

  • AIn which magnetic field is set up
  • BBy virtue of which emf is induced I the armature conductors 
  • CBy which current in ac coil is reveres during the period it is short circuited by the brush
  • DHow armature flux affects the main field film
Correct Answer : (C)

By which current in ac coil is reveres during the period it is short circuited by the brush

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