Post on 14-Sep-2015
description
Cavitations erosion
High-speed reciprocating machines, or machines in which the bearings are subject to high frequency vibration. Gaseous cavitation in machines handling lubricating oils with gas in solution, refrigeration compressors in which the refrigerant is in contact with the lubricating oil.
Cavitation erosion
Cavitation erosion
Electrical Erosion Damage in Journal Bearing Damage in an electric motor after a short run on test following a mechanical overhaul. Damage confined to the loaded area on the bottom half bearing, but is continuous on the journal. Note the shiny melt pits on the surface of the bearing Electrical fault with leakage to earth through bearing oil film
Electrical arcing damage in loaded area of journal bearing
Electrical arcing damage to the journal
Electrostatic erosion damage Typical 'frosting' appearance of electrostatic arcing damage Note that the damage to the bearing is limited to the region of low oil film thickness, the loaded region, of the bottom half bearing, but is continuous on the journal.
Electrostatic erosion damage
Fretting damage Fretting is caused by small scale oscillatory movements. With journal bearings this can occur through external vibration transmitted to a stationary machine. Fretting damage can also occur on the backs of journal bearing shells that are not given an adequate interference fit in the housing
Fretting damage-Journal Bearing
Loss of clearance in tilting-pad journal bearing Loss of clearance in five pad, tilting-pad journal bearing at high-speed start-up causing wiping at the centres of all the padsFailure can be avoided by extending the run up time to full speed or by increasing the radial clearance in the bearing
Loss of clearance in tilting-pad journal bearing at start-up
Lubricant oxidation deposits
Scoring damage of WM thrustpad by dirt
Scoring of lead bronze journal bearing
Tin Oxide formation on WM
Wiping failure
Fatigue of bearing by vibration