Short circuiting in the armature winding is caused due to
Any of the above
Short circuiting in the armature winding is caused due to Failure of insulation between two turns of a coil, Failure of insulation between two commutator bars and Grounding of two or more turns of the same coil.
The ventilating ducts in most of the dc machines are
The armature core of a dc machine is usually made of