If you’ve spent any time looking for a backup power UPS, then you already know that when it comes to an uninterruptible power supply, you have an unlimited number of options. Narrowing them down and choosing the right UPS power supply for your application depends on a number of different factors including UPS system typology, UPS load capacity, and UPS runtime, to name just a few.

Simplify your UPS system choice with a powerful selection tool from Vertiv

Vertiv offers an Intractive Product Selector where you can filter UPS systems by these and many other features, and then compare the options that meet your criteria side by side. It’s a highly effective and time-saving tool for choosing the ideal UPS backup power supply for your specific requirements.

However, to use the Product Selector tool effectively, there are several things you need to know. Let’s back up and start with the basics.

What is a UPS?

In our article aptly titled What is a UPS?, you can find a detailed description including UPS use cases discussing when and why you need a UPS system. The article explains that an uninterruptible power supply provides instantaneous emergency power to critical devices—such as servers and other electronic components found in computer networks—through the energy that is typically stored in a rechargeable battery. UPS power ensures these systems continue to operate properly even when the main source of power fails. Unlike generators or other backup power supplies that can take a few seconds to kick in, a UPS system ensures no break at all in the power current, hence the name uninterruptible power supply. The UPS battery backup carries the critical load until the longer-lasting backup power supplies can engage and take over the job.

What are the differences between the main UPS topologies?

One of the key search criteria you can choose on the UPS Product Selector is product type. There are three different types of UPS typology: online double conversionline-interactive and offline (also called standby and battery backup). In the article What Are the Different Types of UPS Systems? we explore each in detail. But the choice typically comes down to the degree of criticality and sensitivity of the equipment being protected.

Generally, an online double-conversion UPS will deliver the greatest power protection by isolating the critical load from virtually all power disturbances or irregularities in the main supply. It is always online, conditioning incoming power as well as providing battery backup. A line-interactive UPS also provides power conditioning in addition to battery backup and can protect against most power problems, however, there is a 4-6 millisecond break in power when transferring to battery back-up. Finally, the offline UPS protects against most spikes and can ride out many shortages, but it does not maintain perfect power during minor sags and surges.

Should I choose a single-phase UPS or a three-phase UPS?

Single-phase AC power is commonly used for household and light commercial applications, such as lighting and small appliances. Smaller power users, such as schools, office buildings, or smaller edge applications, can choose a single-phase UPS with confidence. However, larger data centers and other commercial and industrial facilities with power-hungry equipment typically require a three-phase power system that can deliver more power with greater efficiency. The article Three-Phase Power: What It Is and the Benefits It Brings provides a detailed explanation.

What power rating do I need to ensure the right size UPS system?

Proper UPS sizing is critical to optimize operational efficiency. Choose a UPS system that is too big, and the unit will be inefficient. Choose one that’s too small, and it won’t be able to support your power load into the future. To determine what size UPS you need, first, determine your current power load and estimate your future power load based on anticipated growth and the addition of newer equipment with higher power requirements. You will then want to choose a UPS system with the capacity to meet your maximum current load with some room to grow.

To do this, you need to consider two things: the power rating in volt-amperes (VA). And the power factor. A UPS system with a power factor of only 0.8 can provide only 80 percent of its rating. A UPS system with a “unity” (or 1.0) power factor will provide 100 percent of its rated capacity. You can specify load capacity from 350VA up to 20kVA using the UPS Product Selector.

What do I need to know about battery chemistry?

The UPS Selector tool allows you to specify different types of battery chemistry, such as lead-acid or lithium-ion. A lithium-ion battery is the most technologically advanced choice. Lithium-ion technology delivers a variety of benefits for UPS systems is a white paper with more information on this subject. However, more traditional batteries, such as VRLA, often have a smaller upfront price tag. You will want to consider operating temperatures, the total cost of ownership, life expectancy, and maintenance requirements to choose the right UPS batteries for your sensitive IT equipment and specific business requirements.

What about the form factor? Where will I mount the UPS?

UPS systems come in a wide variety of form factors and the UPS Product Selector lets you choose from seven different options, including UPS systems that are convertible and can be either rackmount or tower. Other options include mini-towers, floor mountable units, desktop systems, or wall mount UPS systems. Many times, the choice is determined by the available space in your data center environment. Do you have rack space to spare? Or would you rather use wall space and free up the rack for more servers and networking equipment? Some applications will require a UPS system that is too big to fit in the rack, in which case you will need to consider tower or freestanding form factors.

How do I calculate UPS runtime to ensure the right amount of UPS battery backup?

UPS runtime is the amount of time a UPS can supply battery power to the connected load. You can calculate runtime yourself by multiplying UPS battery capacity by UPS input voltage and then dividing the sum by the total supported load (in watts.) Or you can use Vertiv UPS Runtime Calculator to determine the battery runtime for a number of different Liebert UPS models. Simply enter the model and then drag the bar on the interactive graph to the appropriate load amount to see the UPS runtime in minutes. The UPS Selector Tool also allows you to specify your preferred battery runtime at both full load and half load and see only models that meet those criteria.

What else should I consider?

Many organizations are required to (or simply want to) select TAA compliant UPS systems that are manufactured or “substantially transformed” in the United States or other TAA compliant countries. Other organizations look for Energy Star-rated UPS systems to help further efficiency goals. The UPS Product Selector allows you to check one or both of these options to find a wide range of Liebert UPS systems that meet these requirements including single-phase, three-phase, online double conversion, and line-interactive options.

Quickly Find the UPS system that checks all your boxes.

Clearly, there is no shortage of factors to consider when selecting a UPS for power backup. Once you know your specific requirements, the UPS Product Selector can dramatically simplify the work of finding a UPS system that meets your needs. If you need help defining your requirements or narrowing down your options, even more, give Vertiv a call and let our experts help you specify the ideal uninterruptable power supply for your application.

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