Vibration Analysis saves UK Coal £400k
Due to seal damage caused in service, the arm seal had been replaced in-situ, and upon the initial run-up following the remedial works it was noted that excessive noise and vibration was emanating from the drive. PCMS provided analysis and guidance on the location of the fault to allow UK Coal engineers to carry out an immediate repair.
UK Coal engineers, through the experience of ranging arm faults, were in a position where they thought their only option would be to change the ranging arm for the spare that they hold at the Mine surface. To carry out this task, is extremely labour intensive due to restricted clearances on the coalface and has historically taken 48 non-productive hours, carrying significant loss in revenue.
The shearing arm was operated insitu at the coalface, operated at full speed on no load. Data were collected from across the shearerarm using a CSI2140 four-channel vibration analyser and processed using the MHM software. Oil samples were collected and analysed to complement the data collected.
Analysis of the data showed high levels of activity around the high-speed input gears.
- Table 1 shows the initial results, with G2 showing clear indications of stresswaves and very severe levels of gear mesh activity.
- Recommendations were made to change out the bearings and gears on shafts 1 and 2 within the gearbox and inspect the condition of the removed components.
- Upon removal of the gear wheels in question, light tooth surface damage was visible indicating the fault was likely to be a sub-surface defect.
- Table 2 shows the results after, with a significant reduction in the noise and vibration levels reported following the change.
“If it wasn’t for PCMS Engineering pinpointing the fault on the ranging arm, our plan was to replace the arm which would have cost us £400,000 in lost production time rather than the 4 hours planned maintenance to change the defective gears and bearings.” – Martin Norman, Chief Engineer