Bearing cage damage in vertical roller mill

This case study deals with the detection of a damaged bearing cage in a gearbox driving a vertical roller mill in the Hoang Mai cement plant in Vietnam.

Since 2015, an Intellinova Compact online system monitors the mechanical condition of the gearbox using HD condition monitoring technology. Some time after the system was installed, the first signs of damage appeared. Measurement with SPM HD showed increasing shock pulse levels that indicated problems on a bearing cage on the output pinion shaft. On removal of the bearing from the shaft, broken bearing cage parts were found.

Thanks to the prewarning time of about four months, it was possible to replace the bearing during a planned shutdown, thus saving the plant an estimated USD 270,000.