Uninterruptiblepower systems (UPS’s) are often being referred to merely as a “batteries in abox”. While in fact, they are very complex systems which perform numerousfunctions.
Those important functions ensure clean power and continuous uptime ofsensitive electronic facilities.Nevertheless, performingregular UPS maintenance is of crucial importance.Without it, main UPS components will decay in time. To prevent that from happening we adviseyou to schedule regular service visits, which must be done by trained and experienced experts. Performinga regular service enhances your own knowledge about the power system. Understandinghow the main elements of your UPS function is of vital importance. Thisknowledge enables you to more easily identify, and avoid, potential failuresand unwanted delays.
Allow us to introduce youto four primary components of each UPS: 1. Battery This main component can be compared to a “heart”of UPS system. Essential battery function is to “kick in” when the system detects a loss of power from the primarypower source. The main purpose of batteries is to support the connectedload during a utility power failure. This component is the most critical UPScomponent since it guarantees system reliability. Nevertheless, the battery canbe often considered as a part which doesn’t require inspection or maintenance.
Sucha mistake can prove costly and can potentially cause a power failure.The UPS can have many different configurations,but each UPS must contain minimally one battery string. It is possible to addmultiple battery string which will result with runtime and/or redundancy increase.The battery strings are serially connected, so if only one battery fails, thewhole battery string will fail.Experience shows that up to 20% of UPS failures happen due to a bad battery.
This factunderlines the need and importance of regular inspection and maintenance. The most commonly used batteries in UPS’sare valve regulated lead acid (VRLA) batteries, including Geland AGM (Absorbed Glass Mat) batteries. A VRLA battery workson a basis of a pressure-relief valve system.
That means that the negativeplate absorbs the oxygen which is normally produces on the positive plate. Thisprocess prevents the creation of hydrogen on the negative plate. Instead ofhydrogen, the resulting product is water (H2O). In this way, the moisture isretained within the battery. This type of battery never needs watering, andthey should never be opened as this would expose them to excess oxygen from theair. In addition to damaging the batteries, opening also voids the warranty.AGM batteries(Absorbed Glass Mat)This type ofbatteries completely absorb electrolyte in separators. Separators are made of mattedglass fibers.
Significant advantage of this type of batteries is that they are spillproof. The AGM separators are wound around the positive plate and protect itfrom the vibration damage. The battery strings and their components have a verydurable and compact housing. If regularly serviced and used in correctapplication AGM batteries can have twotimes longer life expectancy than the conventional batteries. Gel (GelledElectrolyte) batteriesMost of the traditionalbatteries contain electrolyte in liquid form.
Instead, gel batteries containelectrolyte a gelled state. Because there is no electrolyte in a liquid state, thistype of battery will not leak if tipped on its side. Noteworthy advantage of gelbatteries is increased resistance to significant discharge. This type ofbatteries can have two or even threetimes longer life expectancy, compared to regular AGM battery. 2.
Rectifier First important role of a rectifier in UPS isto charge the batteries. His second function is to convert power from AC to DC.Incase of a power surge, the system recognizes power loss and excludes rectifier fromthe power circuit. Even in that case, power stays unchanged and utility isbeing powered on batteries.
After the utility main power is restored, therectifier starts to charge the batteries. At first, charging process is beingslowed down, to prevent overheating the batteries. Our Company uses a refined charging approachwhich, which greatly slows the decay process. 3. Inverter The UPS inverter receives the DC from theDC buss. In case of a power surge,the rectifier stops providing current to the DC buss, in which case thebatteries become main power source. During the power surge, inverter receives powerfromthe batteries and maintains to run. After power restoration, the invertercontinues to receive DC from the rectifier.
As long as inverter receivespower from any source, he newer stops to run. 4. Static bypass Almostall of the UPS’s contain a static bypass. His role is very important and we canrefer to it as a last line of defense. His function prevents loose of power incase the inverter fails. In that case, static bypass switches the load directlyto the mains input feed. This way, the power circuit is being closed and the incoming power can be transferred tothe batteries, rectifier and the rest of the system.
Main advantage of thisimportant component is that it allows functioning of the critical systems, evenin case of internal UPS components failure. Almost always, astatic bypass is an internal UPS part, but can also contain external switch. Getting familiar with yourUPS and its primary components is important. When you understand main functionsand identify the critical components, you are able to act preventatively and assure optimal performance of yoursystem. Our recommendation is to plan minimally two maintenances each year. Such services shouldincorporate an overall range of critical components inspections, in order to ensurethe good condition of your UPS.