A 6-pole, dc armature with 36 slot and 2 coilsides per slot is to be wave-wound (doublelayer). Calculated the back-pitch, front-pitch and commutator-pitch. How many dummy coils, if any, are required? Draw the developed diagram of the winding and show the locations of brushes and the distance between them in terms of commutator segments. If
(a) 2 brushes are used, and
(b) 6 brushes are used.