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How To Size A UPS System

How To Size A UPS System

How To Size A UPS System

Correctly sizing an uninterruptible power supply system is critical to a reliable source of power. Under-sizing causes immediate problems, while initial oversizing will waste energy, money and valuable floor space. From the combined load of all the equipment the UPS will protect and scope for further system expansion through to battery runtime and redundancy, many factors should be considered when it comes to choosing your new UPS system. Therefore, in this blog, we outline how to size a UPS system to help you do just that. Should you require any further information or help, we encourage you to get in touch, as our friendly team is only too happy to help.

Why Choose A UPS Power Supply System?

A UPS system protects IT equipment and other electrical loads from power issues that hinder supply, performing the following functions:

With such an important role to play, it’s important that you choose the right UPS system for your operation. The first step is to size it, and we outline how to do this, in the next section.

How To Size A UPS System

With a couple of easy questions and calculations, you can determine your power needs and find the right UPS power supply system for your business.

Things which you will require in order to make this calculation:

  • Access to all equipment to be protected by the UPS.
  • An idea of future expansion or growth of the load.
  • The amount of runtime you would like the UPS power supply system to last.
  • Calculator, or pencil/pen and paper.
  1. List all equipment needing protecting by the UPS (remember to include monitors, external hard drives and routers, etc.).
  2. List the amps and volts for each device. These ratings can typically be found on the label on the back of the equipment. Multiply amps by volts to determine VoltAmps (VA). Some devices may list their power requirements in watts. To convert watts to VA, divide the watts by power factor. For servers, the power factor is often 0.9.
  3. Multiply the VA by the number of pieces of equipment to get the VA subtotals.
  4. Add the VA subtotals together.
  5. Multiply the total by 1.2 to get the grand total. This step accounts for future expansion.
  6. Use the grand total to select a UPS. When choosing a UPS, be sure that the total VA requirement of supported equipment does not exceed the VA rating of the UPS.

When calculating the size of a UPS, it’s imperative that you take the following into account:

  • Apparent power (VA or kVA): Defined as S=VxI for single-phase loads, S=(VLI x ILI)(VL2xIL2)(VL3xIL3) for three-phase loads where V is the voltage, and I is the current absorbed by the load under normal operating conditions (EN50091-1-1). This information can usually be found on rating hardware labels, and in the documents and information supplied with the systems to be protected.
  • Overloads: Are voltage and current demands on the UPS in excess of its specification? They could be during initial energising of a system or constant where too much steady state load is connected to the UPS output.
  • System Expansion: The load should be around 90% of the system size to guarantee long-term reliability. A factor should also be added for future expansion of the protected loads. This is typically taken as 25%.
  • High Switch On Current Demands: At power-on, some loads have a high initial switch on current demand lasting for a short time period (50 to 100ms). For example, laser printers, some types of lights, isolation transformers and pumps. For these types of load it is recommended you oversize the UPS by a factor of at least 3, or remove them from the protected system, so they can power down during a mains failure.
  • UPS Runtime: Do you want your UPS to last 20 minutes or 24 hours? It’s important to know how long you require the UPS to last at this stage, as UPS recharge times can be within 4 hours to 90% for small single phase solutions to typically ten times the discharge to beyond 12 hours for long autonomy solutions.

There’s a lot to take into account, but we here at Dale Power Solutions can help with any sizing confusion, and even recommend UPS based on your calculations and power requirements.

Our UPS Power Supply Systems

If you’re sizing up UPS, then it’s likely you’re looking for some new systems. We have a great range available here at Dale Power Solutions, and our expert team can help with recommendations, sourcing, installation and UPS maintenance should you require it. From the DALE E101L (1kVA / 700W capacity), DALE E1015L (1.5kVA / 1.05W capacity) and DALE E102L (2kVA / 1400W capacity) in the Dale E100 Series through to the Dale E73380 (80kVA / 72KW capacity), Dale E733100 (100kVA / 90KW capacity) and Dale E733250 (250kVA / 200-250KW capacity) in the Dale E700 range, our UPS systems are extensive, providing something for every business.

Some of our most popular UPS systems include:

The Dale E631100

  • 100kVA three phase modular UPS
  • High frequency double conversion online technology
  • 19” cabinets available in full and half height format
  • Modular design capable of housing either 5x or 10x power modules
  • 1:1 & 3:3 power modules available in 4, 6 and 10VA ratings
  • Configurable N+1 modular redundancy
  • Intelligent battery charge management
  • Short circuit and overload protection
  • EMI and RFI noise filtering
  • Smart circuit RS232 communication with monitoring software
  • Fully digitized microprocessor
  • Large touch screen LCD interface

Learn more about the Dale E631100, and the Dale E600 range.

The Dale E73330B

  • 30kVA three phase UPS
  • High frequency, double conversion online technology
  • Fully digitised DSP control
  • Advanced battery management
  • Selectable ECO mode for high efficiency operation
  • Automatic battery charge in UPS off mode
  • Lightning and surge protection
  • Short circuit and overload protection
  • Emergency Power Off facility
  • Smart RS232 and USB comms with monitoring software
  • Optional relay or SNMP communications card
  • Up to 4 units can be operated in parallel

Learn more about the Dale E73330B and the Dale E700 range.

Along with the Dale E100 range and Dale E200 range, there is much to choose from, and much that we can do to help.

Sizing a UPS power supply system may seem daunting, but with our help, it becomes a breeze. Ensuring all of your critical power equipment is covered, we can advise you on your requirements, and help you find the right system if you so wish. To find out more, please contact us today on 0330 999 3000, or drop us an email at sales@dalepowersolutions.com. We help businesses across the UK, in areas including Manchester, Liverpool, London and Edinburgh, so are sure we can help you too.