DETECTION OF ELECTRICAL DISCHARGES IN BEARINGS

This is a very informative and officially released publication specifically addressing the VFDs, standing for the "variable frequency drive"s; and the volume was prepared by the recognized specialists of the world-known SKF Company. The use of subject drives is constantly increasing, and that is mostly because of their cost effectiveness.

The makers of these drives have all significantly and so valuably contributed to the above mentioned development by making subject equipment much better and reasonably affordable, and this was done by introducing the PWM - standing for the pulse width modulated - drives. However, it should of course be understood that, along with this newly introduced technology, some more premature bearing technical failures occurred; moreover, increasing number of electric motors fail prematurely.

The main declared reason of these premature failures in the mentioned electric motors was electrical erosion. Dismounted bearing will be showing evidence of the electrical erosion - for example, the grease of the motor is also affected same way the other bearing components are.

One of the proposed ways to diagnose the electrical erosion implies using the oscilloscope with a contact probe on a rotating shaft, however bear in mind that this way is considered expensive and too time-consuming, thus very impractical...​