The compensating winding in a DC machine?

Compensating Winding in DC Machine

Machines that encounter significant load fluctuations will experience a sudden shift in the magnetic neutral axis. The DC machine's armature will experience a statically induced emf as a result.

The statically produced emf in the armature may hit an arc between the segments of segments, causing the entire set of commutator segments to flash over. Pole face winding is another name for compensating winding. Slots in the pole faces have compensating winding placed within them. In order for its mmfs to be proportional to the same current as the armature winding, they are connected in series.

The direction of current in the compensatory winding must be the opposite of that in the armature winding immediately below the pole face in order to counteract the effects of the armature reaction.

Summary:

The compensating winding in a DC machine? (A) Is located in the armature slots for compensation of the armature reaction (B) Is located in the commutating poles for improving the commutation (C) Is located in the pole shoes to avoid the flashover at the commutator surface (D) Is located on pole shoes to avoid sparking at the brushes.

The compensating winding in a DC machine is located in the pole shoes for avoiding the flashover at the commutator surface. Due to their size and higher expense, compensating winding is typically only employed on large machinery that are exposed to significant changes.