Reducing the risk of failure

The key to effective Condition Monitoring (CM) is to understand CM itself before looking at the individual monitoring techniques. Equipment not being fitted correctly or machines not being used for their original purpose are examples of problems that can lead to false readings and a poor understanding of what is happening inside a plant. Ian Pledger, field service engineer at Schaeffler (UK), explains

The first thing you need to have is a good relationship between the engineers on the plant and your CM partner. There is little point in doing CM if the actions you recommend are not followed up. Second, don't try to do too much too soon. It is important to build up the portfolio slowly but effectively so that everyone is onboard at the outset. Third, you need to decide if you are doing the CM yourself, whether you have a dedicated CM workforce or if you are going to do CM as an ad hoc activity. The latter is difficult because CM is not always a priority role for many engineers who are pulled in so many different directions and have limited resources.

However, if implemented correctly, many engineers will be able to avoid a 'firefighting' culture and benefit from a 'prevention is better than cure' approach.

Once these foundations have been laid, it is then a case of deciding on the right tools and techniques for the plant being monitored. There is little point in trying to fit the plant to the CM equipment. The CM equipment must be aligned to the plant. The one tool or technique that makes the difference is always the one that works best for the application or environment in question. For example, vibration monitoring is best suited to monitoring high speed applications because it is easier to obtain more detailed information compared with acoustic emission (AE) monitoring techniques, which are more suited for slow rotating equipment generally above 80rpm.

The latest CM systems are being used to monitor a diverse range of industrial equipment, including pumps, motors and compressors.

Schaeffler's latest CM device for example, FAG SmartCheck, is an ultra compact device that can be used to monitor vibration and temperature, as well as a range of other machine and process-specific parameters such as pressure and flow rate. By monitoring these parameters, users are provided with a broad basis of information in real time, which enables the accurate assessment of machine condition. Due to its patented self-learning (Teach-In) mode, the device's alarm thresholds are adjusted automatically. After set up and commissioning, the unit operates autonomously. The relevant machine parameters are measured and saved continuously in the system, creating a substantial database over time.

Bearing defects in electric motors can be detected early by monitoring vibration and noise levels. German company Schorch Elektrische Maschinen und Antriebe, for example, required a reliable, cost-effective method of monitoring its motors, in terms of both monitoring bearing damage and other parameters such as temperature, load and speed. This comprehensive source of data would provide continuous information about the overall condition of machinery, including difficult-to-access machines or ones installed in remote locations. In order to provide information about the long-term condition of machines in the field, access to historical data was also needed. Schorch installed a FAG SmartCheck device on the drive motor of a piston compressor. Further parameters such as room temperature and motor housing temperature were recorded and correlated with the vibration signals to enable intelligent process monitoring. However, the customer's main priority was the vibration measurement results, which gave an early indication of any damage to rolling bearings.

Other OEMs are also benefiting from CM, for example, on vacuum pumps, FAG SmartCheck can help to identify imbalances, incorrect shaft alignments and bearing damage. These critical operating conditions, if left undetected, could lead to the stoppage of a complete production line.

Due to their flexibility, CM devices can be attractive solutions for machines that are installed in remote locations, for example, flood control pumps in reservoirs. Here, measurement data from the pumps can be accessed remotely using secure, remote Internet connections. Operators are permanently informed about the condition of their machines without having to be onsite and if necessary can take immediate counter-measures if alarm thresholds are exceeded.

CM devices are also being used successfully to monitor the condition of compressors, which are often subjected to heavy loads and considerable vibrations, which means unplanned downtimes can occur suddenly without warning. By installing CM systems, it is possible to reduce these risks.