1.       Mention the location and use of compensating winding in DC machine. Compensating winding is placed under the pole shoe of DC machine that is used to prevent the distortion of the field flux pattern due to armature reaction.

2.       Discuss about “active copper” and “inactive copper” in the design of DC machine. Active copper describes the portion of copper coils lying in the slots of armature and field pole as they determine the electric loading of the machine. Inactive copper describes the overhang portions of the copper coils as they establish the connection between the conductors and form coils.