🔍 Key Concepts

• DC motor armature windings and how current flows through them • Effect of a short circuit on current and magnetic fields • What causes brush sparking, vibration, or failure to start in DC motors

💭 Think About

• Think about what happens to current in the armature when two points that should have resistance between them become directly connected with very low resistance. • How would that change the magnetic field pattern in the armature and at the commutator/brushes? • Which symptom is most directly linked to excessive or uneven current in particular coils that are connected to the brushes?

✅ Before You Answer

• Which option best matches a symptom of localized excessive current in part of the armature? • Consider which effect would be most immediately visible at the commutator/brushes when a shorted turn passes under them. • Eliminate any options that sound more like open circuits or loss of power rather than a short within the armature windings.