Background
In this case study online condition monitoring detects motor bearings deterioration in AHU saving €100,000 in an API pharmaceutical plant situated in Singapore. The plant has adopted Eastway’s cutting-edge online condition monitoring technology to ensure continuous monitoring of both high and medium-criticality equipment, including Air Handling Units (AHUs). In 2018, the plant made a strategic decision to install the Eastway Safeguard® online condition monitoring system on its critical Heating Ventilation Air Conditioning (HVAC) system, thereby replacing its manual vibration data collection program.
The introduction of the Eastway Safeguard® system onto the AHUs marked a significant milestone in the plant’s adoption of best-in-class maintenance standards. By using Eastway Safeguard® system, the plant aimed to reduce downtime, increase production, and avoid unexpected maintenance issues.
In addition to this proactive approach, the pharmaceutical plant has a dedicated maintenance team that collaborates closely with Eastway, facilitating seamless communication and the provision of regular feedback on asset condition.
Case description
In November 2023, high vibration values, both in velocity (mm/s RMS) and acceleration (g’ RMS), were detected above warning and alarm levels across the Air Handling Unit motor test points through the Eastway Safeguard® system. Refer to Figure 1 for the acceleration trend of AHU supply motor 1, drive end, from January 2023 to February 2024, showing this increasing trend, which intensified notably in January 2024.
Figure 1. Acceleration (g’ RMS) trend from motor drive end test point.
Analysis & Recommended Action
Further analysis of the vibration data from the motor was conducted by the Eastway remote monitoring team. The analysis included examining vibration FFT spectra (Fast Fourier Transform) and time waveform signatures. The findings revealed various signs indicative of early bearing deterioration, such as the presence of non-synchronous frequencies and abnormal noise patterns in high frequencies. Figure 2 shows a comparison of acceleration FFT spectra from July 2023 to January 2024, highlighting the increasing frequencies associated with bearing deterioration over time. Based on the analysis, it was recommended to plan for the replacement of the motor bearings.
Figure 2. Acceleration (g’ RMS) FFT spectra at the Motor Drive test point showing frequencies related to bearing increasing over time.
Action taken
Following Eastway’s recommendation, the site maintenance personnel scheduled a downtime window for the AHU motor. They replaced it with a spare motor, while the existing one was sent to the workshop for inspection and repair. Upon inspection, it was found that the motor bearings were worn, with chipped balls and visible damage to the outer race. Please refer to Figure 3, illustrating the velocity (mm/s RMS) trend, which indicates a significantly reduction in vibration values.
Figure 4. Vacuum Pump – Pump Drive End Acceleration Trend from Jan to Aug 2023 showing a high decrease in values after Pump Bearings replacement.
Results
Using online condition monitoring to detect motor bearings deterioration in AHU resulted in reduced downtime and maintenance costs, as well as improved production efficiency by addressing potential issues before they escalated. Close collaboration between the maintenance team and Eastway ensured effective monitoring and timely intervention, leading to successful replacement of AHU motor within a scheduled downtime window.
The table 1 below summarises the importance of having predictive maintenance in place to detect failures, in this case motor bearings deterioration was detected before it progressed to a critical level, allowing corrections to be carried out before costly system failures occurred, thus maintaining operational continuity.
Table 1. Estimated cost savings
