Excessive wear on a coupling between pump and motor flange is most likely caused by:

Excessive wear on a coupling between pump and motor flange is most likely caused by:

• A. Bad bearing
• B. Misalignment
• C. Packing
• D. Abrasives

Answer: (B)

Misalignment between the pump and motor shafts is the main culprit. When shafts aren’t perfectly aligned, the coupling must accommodate angular or parallel offsets, creating bending moments and uneven contact on the coupling faces. This leads to increased friction, heat, and wear at the flange surfaces, and the resulting vibration compounds the wear. A bad bearing can cause misalignment, but the wear path for the coupling flange itself is driven by the misalignment. Packing and abrasives affect seals and other components, not the direct wear of the coupling flange. Keeping proper alignment and a solid foundation is essential to prevent this wear.

Misalignment between the pump and motor shafts is the main culprit. When shafts aren’t perfectly aligned, the coupling must accommodate angular or parallel offsets, creating bending moments and uneven contact on the coupling faces. This leads to increased friction, heat, and wear at the flange surfaces, and the resulting vibration compounds the wear. A bad bearing can cause misalignment, but the wear path for the coupling flange itself is driven by the misalignment. Packing and abrasives affect seals and other components, not the direct wear of the coupling flange. Keeping proper alignment and a solid foundation is essential to prevent this wear.