Sparking in DC Generators

The following are the most probable reasons to cause sparking in DC generator.

• Due to brushes
• Due to armature
• Due to commutator

Sparking due to Brushes

• In correct position of the brushes.
• Unequal brush spacing.
• Worm out brushes.
• Inadequate pressure on brushes.
• Carbon brushes short circuit more segments at time.
• Wrong grade of brushes.
• Brushes not properly bedded.

Sparking due to Armature

• Overloading of armature.
• Earth fault in armature windings.
• Short circuit in the armature coils.
• Play in the armature.

Sparking due to Commutator

• Weak mica between segments of commutator.
• Rough commutator surface.
• Commutator is not fully round.
• Segments short circuited by carbon filing.
• Oil and dirt on commutator surface.

Sparking due to Pole

• Projection of intersegment micas.
• Reversed interpole polarity.