Uninterruptible Power Supplies (UPS) are often the first line of defence to protect your critical load equipment. They continuously take over the incoming mains’ power with all its shocks and surges and perfectly regulate a clean, stable power supply.
Careful planning and significant investment in UPS are part of an energy protection strategy and even business continuity planning. If a UPS works properly, you will forget it is there. But should you?
Once a UPS is installed and commissioned, it can sometimes be left until the next alarm before you think about it. With UPS becoming a commodity product and the original price of the product falling, some manufacturers are now starting to charge a premium for ongoing servicing and ‘maintenance’. But what exactly does this “maintenance” entail? So, one of the most common questions we have been asked by users over the years is: what should we include in our UPS service and maintenance contract? Do I even need one?
What is a UPS?
A UPS is an electrical device designed around sophisticated electronics contained in a metal or plastic box. Apart from a cooling fan, it has no mechanical moving parts, like a spare diesel generator, so what might need servicing? Very little, in fact, and the term ‘maintenance’ for work carried out during a UPS visit is probably now misused. There is very little, if any, “maintenance” that can be carried out during an engineer’s visit to a UPS unless he is specifically replacing obsolete parts. So why do I need a contract or agreement?
Although cooling fans are probably the only mechanical moving parts in a UPS (they can be cleaned or in some cases lubricated). The rest of the device is built around electronic devices that switch a fantastic amount of electricity tens of thousands of times per second. It is all run by algorithms written in firmware and controlled by digital signal processors (DSPs). These complex electronic switches have a finite design life, and if they are used long enough in the wrong conditions or in the wrong environment, they will eventually wear out and break down. When they break, they are likely to short-circuit, causing one of the loudest bangs you’ll ever hear, as well as smoke that can set off the fire suppression system.
UPS Operating Conditions
These devices (which are essentially complex circuit breakers) are designed to operate for up to 20 years, but only under the environmental conditions and load limits for which they are designed and manufactured.
Therefore, most of the time spent by UPS engineers on ‘service’ visits as part of a service contract or agreement is related to testing. Basically, they check that the UPS is operating in the correct environment under the correct load and that it has not been damaged by any external factors. Some of these ‘checks’ can and are carried out by the user on a daily basis. UPS room temperature, safe UPS output load, even for the brave – use of the built-in battery testing function, while following the basic principles of not having too much dust, moisture, clutter or teacups in the UPS room (Yes, too often UPS can become handy shelves)!
However, just as important as these basic checks are those that need to be carried out by an experienced UPS engineer.
Technical Issues
Once the correct switching procedure has been mastered and the UPS is safely switched off while maintaining the critical load through the bypass line, the UPS can be subjected to a detailed visual inspection of all components, connections checked and tightened where necessary, signs of corrosion noted and, if the environment is unfavorable, excess dust deposits removed. DC and AC capacitors, and batteries should be visually inspected for cracks, leaks or overheating, all signs that components may be failing.
If the visual checks are correct, the UPS engineer can restart the UPS and take load readings. On the DC side of the UPS, both voltage and AC ripple can be measured. Output AC waveform measurements may indicate aged AC filter capacitors. Analyzing the UPS input current can also highlight network problems such as high harmonics, poor power factor or even just high voltage – temporarily the UPS is designed to filter these network problems from the critical load, but continuous operation at higher than rated input voltage or high harmonic content will cause premature ageing of the UPS components. If external factors cannot be eliminated, this should be taken into account and recommended measures should be taken in good time.
Although the user can clearly see all current UPS alarms, usually only the UPS engineer can download and analyses detailed history logs of the conditions to which the UPS has been exposed and how it has performed since installation (or the last service visit). This is essential information for predicting how long components such as capacitors and batteries will last.
Finally, firmware – depending on the age cycle of your UPS, it may have a recently updated firmware version to control complex electronics. Only an experienced and trained UPS engineer should attempt this. The new firmware is very important to prevent unexpected events, which unfortunately have already been reported by other users of the same product. The update protects you, so it is worth insisting, especially if it is recommended by the manufacturer.
Complex Task Tracking
With our sophisticated job management software, we can ensure that you, the customer, receive a timely report as soon as a service has been performed. Our engineers have access to your system information, spare parts schedule and potential problems based on UPS history. This means we are always prepared before arriving on site and can ensure your system is well looked after throughout its lifetime.
Our Findings
Finally, you should report any findings during a service visit quickly, clearly and transparently. You can then make decisions or ask for help or recommendations on how to proceed.
