As shown in the illustration, which brush holder would be appropriate to use in a bi- directional motor? EL-0029

Correct Answer: Option A — radial mount

Radial mount brush holders are oriented perpendicular to the commutator surface, allowing brushes to maintain equal contact pressure and stability regardless of the direction of armature rotation. This symmetric design is required for bi-directional motors to prevent excessive brush chatter, sparking, and uneven wear.