What are the damage symptoms of mechanical equipment bearings due to lack of oil or grease?
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When the bearings of rotating equipment are damaged, what signs can be used to determine that the damage is caused by a lack of lubricating oil or grease?
Abnormal noises, excessive vibration, and rising temperature.
Abnormal noises, increased vibration, rising bearing temperature, and it is also possible for the bearing to seize.
In the initial stage, there are abnormal sounds and increased vibration; later on, rising temperatures lead to rapid burning. Post-incident signs include dry friction, blueing due to high temperatures, and burn marks； However, during operation, it is necessary to distinguish between high bearing temperatures caused by an excess of oil or grease
It’s best to check the spectrum before maintenance; if there is no spectrum, you can consider the ratio of sound to vibration
The rollers turn blue or black, the grease remaining in the bearing housing or bearing caps turns black, and the cage breaks into multiple pieces; this is unacceptable.
In the early stages, it can be determined by listening for any noises inside the bearing housing, sudden increases in temperature, and increased vibration. After opening the bearing housing, it is possible to determine whether damage is caused by lubricant issues by checking whether there is lubricant inside the bearing, smelling for any burnt odor, observing the color of the lubricant in the housing, and checking whether the bearing rollers are blue or black in color as well as whether the retainers are black or blue in color
Blackening and bluing of balls and raceways, color of grease, smell of burnt grease