FAQ

An uninterruptible power supply or UPS (Uninterruptible Power Supply) system is an electrical device that provides emergency power to a load when the input power source or utility power fails.

A UPS system has three main functions: it conditions the incoming dirty power from the utility company to provide you with a clean, uninterrupted power supply, it provides pass-through power to accommodate sags or transient power interruptions, and it allows seamless switching of the system during a complete power cut.

Phases of a UPS, such as a single-phase UPS or a three-phase UPS, describe the number of electrical phases that a UPS receives and transmits. Electricity companies generate three-phase power because it is the most efficient way to transport electricity over long distances.

For larger power consumers, such as large data centers, industrial manufacturing, and hospitals, the power remains as three-phase, requiring a three-phase UPS. For smaller power consumers, including residential or office buildings and most schools, the power is converted to single-phase power.

UPSs are rated in volt-ampere (VA) ranging from 300 VA to 5,000 kVA. This rating represents the maximum load a UPS can support, but it may not exactly match the load you have.

To allow room for growth, the best practice is to choose a UPS with a VA rating of 1.2x the total load you need it to support. If your UPS supports motors, variable speed drives, medical imaging devices, or laser printers, add more VA capacity to your requirements to account for the high currents that occur when these devices start up.

Companies that expect rapid growth should use a multiplier higher than 1.2x. Newer server hardware often has a higher power requirement than older models, so factoring in additional VA will result in more and newer equipment being added.

The duration of the battery at a certain charge level is called the battery's "autonomy". A UPS battery can be sized from a few minutes to a few hours, but the cost of a large battery with a high load can sometimes mean that a diesel generator should be considered.

Increased 'autonomy' is achieved by adding additional battery strings connected in parallel, but it is important that the load capacity of the UPS system is taken into account.

UPS systems are grouped by topology, which refers to how the UPS and the power grid interact. This translates into the level of efficiency and reliability you can expect from your power source. There are three main types of UPS topologies:

Standby UPSs allow equipment to shut down until the UPS detects a problem, at which point the UPS switches to battery power to protect against sags, surges, or interruptions. This topology is best suited for applications that require simple backup or with less sensitive equipment, such as small offices/home offices and point-of-sale equipment.

Line-interactive UPSs actively regulate voltage by increasing or decreasing voltage from the utility grid before passing it on to the protected equipment or by drawing on battery power. Line-interactive models are ideal for applications where protection against power disturbances is required, but the mains voltage is relatively clean. Main distribution board (MDF) and intermediate distribution board (IDF) communication cabinets, non-centralized server and network rooms and general IT enclosures are ideally suited for this topology.

Online UPSs provide the highest level of protection by isolating equipment from raw utility power from AC to DC and back to AC. Unlike other topologies, this dual conversion method does not provide transfer time to the battery for sensitive equipment, as the electricity is already coming from the UPS. The online, double-conversion UPS topology is best applied to mission-critical equipment and locations where power supply is poor or highly unreliable.

ECO mode is often referred to as 'Active Standby' and is mainly used in places where the general mains supply is relatively stable or where the load is not sensitive to mains disturbances. The UPS runs in bypass for normal conditions and transfers the load, without interruption, to the inverter (on-line mode) when the utility power fails.

Form factors refer to the form orientation of the UPS and how it is installed. Most UPSs fall into one of two form factor categories: rack-mounted or free-standing as a tower.

Mounted UPS systems can be installed in a server rack or a wall. These are usually single-phase UPSs, but several manufacturers offer a number of rack-mount UPSs that are three-phase or multi-phase UPS models. A rackmount UPS is ideal for organizations that want to save space by consolidating equipment into a rack or enclosure or by utilizing traditionally underutilized wall space.

A tower or freestanding form factor is available for UPS systems of almost any size. From small SOHO UPSs to data center UPSs that are too large to fit in a rack, the tower form factor is a popular way to save rack cabinet space or deploy individual UPSs for a decentralized power protection architecture.

Choosing a UPS is more than determining the size and shape you need. The additional features available with different UPS models vary widely and vary from manufacturer to manufacturer. This can help you when choosing between the different UPS systems on the market.

Extended run time UPS systems:

Most UPS systems are equipped with internal batteries to support their electrical load for 10 to 15 minutes. However, some applications require more battery backup.

Extended Battery Modules (EBMs) are additional batteries that can be connected to a UPS to extend runtime. Depending on the percentage of the total load of the UPS you are using and the number of EBMs connected, a UPS can easily reach runtimes of several hours.

• Generator Compatible UPS:
  If you have the space you need, coupling a generator with a UPS ensures that your backup power system will get you through any power outage imaginable. When a UPS and generator are operated together, the role of the UPS is to maintain power for one to five minutes, which is how long it takes for a generator to start up.
• Network-connected UPS:
  If you have a decentralized power protection architecture, you know the importance of having a UPS with network monitoring and management capabilities. Remote visibility on all your UPSs is not just a matter of convenience. It allows you to solve problems quickly without wasting time traveling from location to location.

The main advantages of using a modular UPS system is the ability to increase the power of the UPS when needed. The UPS modules are hot swappable and can be added at any time in the future. Modular systems will normally accept one or more additional power modules to achieve their rated capacity, making them inherently "N+1" and providing redundancy.

Other benefits of modular UPS systems include efficiency and time to repair. A UPS system operates at peak efficiency when it approaches its maximum rated capacity. Repair can be achieved by replacing an entire power module rather than troubleshooting down to the component level. A customer can keep a spare power module on site so that technicians on site can repair a faulty device.

A surge protector offers just that: protection against overvoltage. A UPS provides surge protection, as well as continuously regulating the incoming voltage and backing up the battery in the event of a power outage. You will often see surge protectors connected to a UPS for additional surge protection and additional output connections.

During a power outage, you need enough battery runtime to power down systems gracefully or switch to a backup generator. You can add an optional External Battery Module (EBM) to extend run time.

There may be a significant extension of the autonomy time. In general, a UPS that delivers five minutes at full load will deliver fifteen minutes at half load.

Power problems are indiscriminate and can affect anyone. Your PCs, servers and network are just as important to your business as a data center is to a large corporation.

Downtime is costly in terms of hardware and potential loss of goodwill, reputation and sales. Also add the delays that inevitably occur when restarting blocked equipment, recovering corrupted files, and rerunning processes that were interrupted.

A sound power protection strategy is cost-effective insurance.

Today's high-tech IT equipment and control units are much more sensitive to electrical disturbances and are more important to the critical functions of many companies than in the past. As a result, power quality problems are more common today and more expensive than ever.

No. In many cases, failures can cause imperceptible damage to circuits and other components, a leading cause of premature equipment failure and problems such as computer lockups. Many power quality issues remain unresolved, resulting in loss of revenue and data.

The reliability of the power is usually stated as a percentage of the time the power is available (see table). For example, the power grid in the US and Western Europe offers three nines of reliability - the power is available 99.9 percent of the time. Because that 8.8 hours of downtime translates into significant costs, IT and telephone network services need at least five nines of reliability.

Irregular flow is a waste of valuable time and money. Exposing their phone systems (and other electronic equipment) to an inconsistent power supply leaves customers vulnerable to hardware and software damage, data corruption, and communication failures. The time and cost of replacing equipment, as well as the loss of business during breakdowns and replacements, can have a major impact on the bottom line.

A generator will NOT protect your equipment from power problems. You need a UPS to ensure that the equipment remains operational until the generator comes on and stabilizes, which often takes several minutes.

If the UPS is overloaded, for example if the protected equipment and/or load draws more current than it can supply, the UPS transfers the load to bypass (for several minutes) until the overload condition is reversed. If the overload condition persists, some UPS models will automatically shut down.

There are two possible answers: (1) the UPS is undersized (for example, the load is 1200 VA, but a 1000 VA UPS is included), or (2) you have more equipment connected to the UPS than the UPS is designed for .

While UPS systems are generally robust and reliable, they require constant monitoring and support. The power management software continuously monitors and diagnoses the health of the grid, batteries, energy resources, and the health of the UPS's internal electronics. The UPS software and connectivity cards enable remote monitoring and management. As well as providing a clean shutdown and control of the load elements.

UPS systems may have the ability to alert fileservers to shut down in an orderly manner when a fault has occurred or to notify users by text/email.

Using an external alarm panel, UPS system alarms are simulated at the external alarm alerting users to the UPS anomaly. The UPS can also provide alarms to the building management system. Another possibility is an SNMP/network card mounted in the UPS, which can alert key personnel via e-mail or text messages.

Yes, an external environmental sensor provides temperature and/or humidity information via the SNMP/network card.

• The rectifier converts AC voltage into DC voltage, charges the batteries and maintains the driving voltage. It handles overloads and buffers and can accept large input voltage fluctuations.
• The inverter converts DC voltage into AC voltage, regulates and filters AC voltage.
• The static bypass automatically connects the load to mains if the overload or fault occurs.
• The battery provides backup power when the mains power fails.

• Possibility of total isolation for UPS maintenance, without disrupting the load.
• Completely safe and easy to use, simple switching sequence, no risk of UPS back-feeding.
• The use of electric locking ensures a 'no-break' transfer without complex and expensive key locking.
• Can be easily modified to accommodate larger clamps for oversized cables.
• Can be built with full MCB/MCCB protection or insulation only, depending on site requirements.
• The unit can also be fitted with shunt trip facilities for emergency power off (EPO) on the input and bypass contactors.
• Can be installed outside normal hours by a qualified electrician, allowing the UPS to be installed during normal hours without further shutdown.
• Possibility for 'two input' systems that provide more flexibility and security for the critical load.
• Local MCB/MCCBs make it possible to slim down the cables locally without additional protective devices.

The quality of the battery can be determined by its 'design life', usually between 5-12 years for VRLA batteries. The 'service life' is not and will never be a guaranteed service life and depends on various factors such as environment, temperature, maintenance, number of discharge cycles, charging regime, etc.

Based on our experience, we generally expect that a good quality '10-year battery', subject to installation guidelines and optimal environmental conditions, will need to be replaced after approximately 8 years.

10 years is the general term given to high integrity batteries that fully comply with IEC60896-2 in terms of construction, performance and design life. Usually they cost a little more than standard sealed lead-acid batteries. They offer a 10-12 year service life, copper threaded plug-in terminals, flame retardant material (UL94-VO), and are generally selected for high-end installations such as hospitals and telecommunications.

One of the most important factors of battery aging and performance is ambient temperature. The optimum temperature range for a VRLA battery is 20-25°C. Higher ambient temperatures improve performance, but quickly age a battery. 20°C is the optimum battery temperature. At 30°C, battery life is cut in half.

If the ambient temperature around a battery pack is not controlled, premature failure of the batteries can occur, leading to costly battery replacement and invariably system downtime.

A battery failure due to overheating can also lead to a complete system failure, which only becomes apparent when the battery pack is placed under load during a power failure.