Motors and drives in the water industry typically have an operational life of 15-25 years, yet we routinely encounter assets in service that are far older. If those assets suddenly fail, what then? ABB’s George Dodwell explains why running assets far beyond their expected lifespan is not a good recipe for resilience.
Recently I was at a site when a particular electric motor and pump caught my eye. On first glance, it looked fairly unremarkable, but upon inspecting the nameplate I realised that the pump was manufactured by Harland Engineering in the early 1950s – long before the introduction of IE classes, EU MEPS, or even the widespread use of drives. Far from being a museum piece, this pump was still in continuous use at a UK water treatment works, more than 70 years after it was first installed.
This is not an isolated example, and we routinely see motors from the 1950s or 60s running on critical processes, as well as drives that have been in service since the 80s or 90s. Pumps, motors and drives are all extremely reliable, and when properly maintained can easily run for several decades without incident. Indeed, it’s testament to the build quality of these assets generally, as well as the diligent maintenance carried out over the years, that this one was still going strong.
However, these assets are not indestructible, and on a long enough timeline, eventually the motor will fail. The question is, what happens then? If the original manufacturer is no longer in business then spare parts are going to be difficult to find, while finding a service provider who can repair or rewind what is essentially an antique may prove challenging. There are no rules forcing you to upgrade older assets, but there’s nothing to stop you finding out how old the assets driving your critical pumps are, as every ageing motor or pump can potentially compromise resilience and create a risk to supply.
So why are these older assets not being replaced? In theory, anything older than 20 years should be considered a failure risk and therefore a strong candidate for immediate replacement. Cost, downtime risk, and the complexity of carrying out the work, are often cited as the main barriers. It may be difficult to source an appropriate replacement, and installing it may not always be straightforward. Old motors won’t necessarily fit into modern IEC frame sizes. If the asset – whether it’s a Harland pump or an old Heenan drive – is showing no outward signs of wear, then it can easily be overlooked in favour of other assets in more urgent need of attention.
These older assets have typically lasted so long because they were built so robustly. Because of this, they are often installed in some of the most critical and heaviest duty applications. However, this means that when they fail, the knock on effects can be catastrophic – and the bigger the asset, the bigger the problem. Proper maintenance can extend a motor’s lifetime by decades, but it only get you so far, and one day the motor will fail irrecoverably. Letting that happen without a plan for what to do can potentially be extremely costly.
In a duty/assist/standby configuration you can afford to temporarily lose one, possibly two pumps at the same time. While this would still be a major headache, the assist and/or standby can potentially buy enough time for a suitable replacement to be found. However, if all three motors are of a similar age, in a similar condition, and all fail at a similar time, then this can potentially be disastrous. It may take several weeks for new assets to be delivered to site, and may take some time to install due to their complexity. Temporary replacements can be hired in to ensure critical processes are kept running, but this will come at a cost.
Utilities can be reluctant to upgrade if they don’t have to, and particularly if the old asset is showing no outward signs of slowing down. Yet the cost of replacing may not be as prohibitive as it seems. Compared to an IE2 induction motor, a latest generation IE5 ultra high efficiency motor will cost a fraction of the amount to run through vastly reduced energy costs, with payback times often measured in months or even weeks.
If you’re upgrading from a motor that’s 50 or 60 years old, and also introducing a drive where there previously wasn’t one, the energy savings can potentially be vast. As well as saving energy, the latest drives and motors also offer improved reliability and lower maintenance requirements. Older motors were often installed with no form of variable speed control. Introducing a drive will not only improve the control over the process, but also reduce wear on system components.
The first step to tackling this problem is simply knowing your assets. Carrying out a Life Cycle Assessment can help to identify the drive or motor assets most at risk, and allow you to prioritise based on age, criticality and condition. Knowing what you’re dealing with allows you to assess your options and protect or upgrade your assets accordingly. It’s amazing how long these old motors and drives can last with proper maintenance, but one day they will need to be replaced. The cost of not doing so, and waiting until it’s too late, will far outweigh the cost of upgrading in a timely manner.
To find out more about the ABB Energy and Optimisation Appraisal, or to discuss your company’s assets and energy usage in more depth, search for “ABB Water Challenge”.
