Question 256Electricity & Electronics - QMED

The correct answer is B) counteract armature reaction to maintain the brushes in the neutral plane to minimize brush sparking. Interpoles in a DC generator are used to counteract the effects of armature reaction, which is the distortion of the main magnetic field caused by the current flowing in the armature windings. This distortion can cause the brushes to move away from the neutral plane, leading to increased brush sparking. The interpoles create a magnetic field that opposes the armature reaction, helping to keep the brushes in the neutral plane and reduce brush sparking. The other options are incorrect because: A) the main field poles, not the interpoles, are responsible for the main magnetic field; C) residual magnetism is provided by the field windings, not the interpoles; and D) the interpoles do not have any function related to the static balance of the stator.