To oppose the shunt field

To oppose main field

To assist the shunt field

To oppose armature

Trailing Pole Tip

Temporary Pole Tip

Topmost Pole Tip

Temporary Present Tip

General Neutral Axis

Geometrical Neutral Axis

Geographical Neutral Axis

Geometrical Numerical Axis

By changing commutator

By reversing direction

By shifting the brush position

By changing armature

Reduce armature reaction

To produce flux

To reduce humming

To reduce friction