Detecting bearing damage

Defectice Bearing

Problem

Rolling bearings can be damaged by improper installation, incorrect operating clearance, inadequate lubrication or excessive loads. If a damaged bearing is not detected, the entire machine may fail.

Solution

The solution is to perform a diagnosis of bearing vibrations with regard to bearing damage. Besides the existence of a damage, the affected bearing component is also determined.

Product: Measuring kit for machine protection

Example

An increased vibration acceleration in the frequency range 1..10 kHz was detected at a bearing during a regularly measurement. Periodic peaks with amplitudes of up to 40 m/s² were detected in the InnoScope oscilloscope module. This could indicate bearing damage.

An envelope analysis was carried out in the InnoAnalyzer module in order to investigate the damage found more precisely. The rollover frequencies of the damaged bearing components become visible. The rollover frequencies depend on the size and geometry of the bearing.

A bearing of type SKF NU230E was used, for which the following damage frequencies can be specified:

Inner race: 10,85 x rpm

Outer ring: 8,15 x rpm

Ball: 3,46 x rpm

Cage: 0,43 x rpm

The envelope analysis shows clear lines at 8.15 times the speed and multiples of it. This clearly allows the bearing damage to be assigned to the outer ring. The damage is also at an advanced stage, which can be concluded from the height of the lines.