Baseline measurements were recently taken on a mill stand gearbox for a new customer in the steel industry. Bearing and gear information was provided for the stand (see below).
Using ITR’s proprietary data collection unit and analysis software, a significant bearing issue was discovered despite not having any prior measurements for comparison. Low amplitude harmonics were detect spaced at 9,188 cpm, which was sourced to the outer-race defect frequency (BPFO) of the gearbox input bearing.
Due to their demanding rolling schedule, the customer did not have an opportunity to inspect the gearbox for 3 months. ITR shortened the intervals between measurements to monitor this vibration for evidence of rapid degradation. After 3 months of operation the gearbox input bearings were replaced and the ITR analysis was verified – Extensive electrical fluting on the gearbox input bearing. A grounding brush was installed to prevent the fluting in the future and maintenance/reliability resources were allocated efficiently by trusting the experts at ITR.