Last Answer : Armature coil is short circuited by brushes when it lies along neutral axis.
Last Answer : Open circuited armature coil of a D.C. machine is identified by the scarring of the commutator segment to which open circuited coil is connected and indicated by a spark completely around the commutator.
Last Answer : If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.