20.06.16
Improving DLR asset reliability with innovative monitoring
Source: RTM Jun/Jul 16
An innovative wireless condition monitoring project is helping KeolisAmey Docklands (KAD) get the earliest possible alerts to bearing failures, improving safety across the fleet. Justin Southcombe, commercial director of Perpetuum, explains.
Train, track and traction motor maintenance has been fundamentally changed with the arrival of Perpetuum’s battery-free wireless condition monitoring technology. Coupled with powerful analytical software, this technology is making condition monitoring and asset failure easier to view, manage and predict.
In 2015, KAD contracted Perpetuum to monitor the condition of its traction motors while they are in service and improve the reliability of its assets on the high-availability Docklands Light Railway (DLR). Perpetuum consequently worked with the KAD engineering team to reduce the turnaround on railway assets for maintenance and renewals. The results have been extremely positive and Perpetuum’s technology is now installed on 20 traction motors on five trainsets.
KAD’s decision to mount sensors at the vibration source on the train is providing the earliest possible alerts to bearing failures, allowing the system to improve safety across the fleet. As the busiest light railway in the UK, with more than 115 million passenger journeys in 2015, KAD has a responsibility to continue delivering excellent service and customer satisfaction.
Part of the process of commissioning the system is to use independent measurements and other sources to configure the calculations and calibration, such that the Health Index reported for the motors provides an unambiguous identification of healthy versus damaged motors. KAD has provided measurement data taken on the Traction Motors (‘Dsel’ values), which has then been used to derive a ‘Motor Health Index’ (MHI) algorithm.
The DLR measurement data was taken from traction motors fitted with FAG bearings, using a manual monitoring device.
The device was used on the wheel lathe, with the motor rotated to provide a simulated idea of vibration. A key part of the delivery of the Perpetuum monitoring solution is calibration – demonstrating the health of an asset can be measured whilst in service.
Figure 1 – Plot of scaled DSel vs Motor Health Index for each of the 20 traction motors across the 5 DLR trainsets (using values immediately prior to the DSel measurement dates).
The results in Figure 1 illustrate that the MHI data obtained by the Perpetuum system shows good agreement with the provided DSel values and there is clear separation of good and poor condition traction motors. In particular, if a traction motor has been measured with a high DSel value in recent readings, then it will always appear with a high MHI.
These types of results instill confidence that the system will reliably identify a degrading traction motor, even at an early stage of bearing degradation. In some cases, traction motors are shown here with a high MHI but only a marginally higher DSel value. Despite this, the Perpetuum data shows clear differences in the vibration profile compared to other well-behaved traction motors clustered in the bottom left hand corner. The data required for this report was generated within three months of fitment, providing a swift means of ensuring component safety and performance.
Armed with this rich information, it is possible for maintenance programmes to become smarter and increasingly efficient because asset life cycles can be extended according to the actual health of the asset, rather than being based purely upon the time it has been in service. This in turn has major benefits for customer service as well as the bottom line, especially as the data can be used to monitor not just the rolling stock, but the track too – at exactly the same time.
In conclusion, there is no doubt that train maintenance has fundamentally changed over the past few years. Perpetuum’s proven wireless condition monitoring technology enables train maintenance, condition monitoring and asset failures to become easier to manage and predict. All of this is backed up with the service and knowledge needed to make it a truly bespoke package for the assets that need to be managed.
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