Which three mounting angles are considered for brush alignment?

• A. Radial, Axial, and Tangential
• B. Radial, Leading, and Trailing
• C. Vertical, Horizontal, and Diagonal
• D. Circumferential, Radial, and Axial

Answer: (B)

Brush alignment focuses on how the brush sits against the rotating commutator to ensure smooth current transfer and minimize sparking. The three mounting angles used areRadial, Leading, and Trailing. Placing the brush radially means its face is oriented perpendicular to the shaft, which gives even wear and consistent contact across the commutator surface. The leading edge is the part of the brush that first encounters the commutator as it turns, and the trailing edge is the part that leaves last; skewing the brush so these edges meet and depart in the proper sequence helps control arcing and wear by aligning the contact with the motion of the commutator and the electrical transitions between segments. Other angle terms like vertical, horizontal, diagonal, axial, or circumferential don’t describe the standard brush-face orientation used for this purpose, whereas radial with leading and trailing covers the practical mounting approach.