
238 Appendix A
Q11.
Bearings fail prematurely
A11.
• Damaged impeller
• Impeller partially clogged
• Rotating elements not balanced
• Excessive radial loads on rotating parts
• Excessive axial loads
• Bent shaft
• Bore of impeller not concentric with outer diameter or not square with hub face
• Misalignment of pump parts
• Misalignment between pump and driver
• Pump operates for prolonged time at low flow rate
• Improper base plate or foundations
• Rotating parts running off-center from damaged or misaligned parts
• Improper installation of bearings
• Bores of bearing housing not concentric with bores in water-end ...