Why Do You Need an Uninterruptible Power Supply - UPS

Uninterruptible Power Supply, UPS device, battery backup power supply, critical power backup or backup power systems are some of the different terms used to describe a UPS explains Sales Director Adam Baverstock in our latest blog.

With over 20 years’ experience as an independent UK based company specialising in sales and maintenance of all standby power products, in this article we discuss the importance of having the right size and design of UPS for your business.

What is an Uninterruptible Power Supply?

An uninterruptible power supply essentially provides critical short-term backup power in the event of any disturbances or disruptions when your regular mains power source fails, or the voltage drops to an unacceptable and harmful level.

A UPS is an electrical device, with either internal or external batteries that stores power to supply energy to connected devices if normal power is interrupted.

In the event of a power failure, the UPS instantaneously switches to a temporary battery source and protects computers, IT equipment, telecommunications networks, and other vital electrical equipment, infrastructure, and machinery against unexpected problems.

Sometimes the biggest causes of downtime and data loss to businesses in the data driven world we operate in today is critical power interruptions.

Loss of Power Can be Catastrophic

In the 21st century, where we have become heavily dependent upon the continuous availability of electricity, a loss of power can be catastrophic.

Organisations in almost all sectors are reliant on a clean consistent supply to keep technology operational 24/7/365. Computers, telephones, and many other pieces of equipment require continuous power to maintain productivity and efficiency.

Any unexpected disturbance in the electricity supply can lead to damaging disruptions to business operations, and the resulting downtime and data loss can cost businesses thousands of pounds a minute in sales and hours of lost productivity. In the worst case situation, it could even lead to death and serious injury to staff or customers.

According to APC, one of the leading UPS brands we work with, every year billions of dollars are lost in the US due to downtime caused by power disruptions that could have been prevented by a UPS.

For Fortune 1000 companies:

  • Average annual cost of unplanned downtime, $1.25—$2.5 billion
  • Average hourly cost of infrastructure failure: $100,000
  • Average hourly cost of critical application failure: $500,000—$1 million

From computers that we use at home to industrial scale production facilities that require constant reliable power, the intelligent technology that we have become so reliant on to operate, it has never been more crucial to make sure your power supply is protected.

How Does a UPS Work

Uninterruptible Power Supply devices offer instant battery backup protection against power loss by providing instantaneous critical emergency back-up power for a short period of time.

They provide enough time for either the connected equipment to safely shut down with minimal risk of damage or data loss, or for an alternative power source such as a backup generator to kick-in.

Many UPS devices can also monitor the flow of electricity to protect against additional problems such as power surges and energy spikes.

Most modern online UPS systems can also correct a wide range of common power problems, including:

  • Sags: short periods when the voltage is below the usual mains supply level
  • Blackouts: are one of the most common types of power problems when there is a total crash of the power grid.
  • Brownouts: an undervoltage similar to a sag, but over a longer period (several hours or even days)
  • Power surges: The opposite of a brownout where there is a sudden increase in voltage caused by an event such as a lightning strike.
  • Harmonics: a distortion from the ideal sinusoidal waveform
  • Unstable frequency: where the power oscillates at something other than 50 Hertz (sometimes referred to as electrical noise)
  • Spikes: very short millisecond bursts of energy on the power line causing sudden increases in voltage.

Continuous Power
All forms of UPS regardless of size provide instantaneous, continuous supply of power without any breaks if the mains electricity power supply should suddenly fail. If longer backup is needed, then a UPS can also maintain power between mains failure and a generator starting up.

Power shifts
Protects from power shifts that can cause damage to electronic devices. The UPS controls voltage instability through a stable power output.

Surge protection
A UPS constantly monitors the incoming voltage and identifies spikes and surges. If harmful changes are detected, the UPS will switch to DC power, stopping the spike from reaching any connected devices. When the spike has gone, the UPS simply reconnects its output to the AC power coming from the mains.

Different Types of UPS Available

When shopping for a UPS, it is important to research and speak to an expert to get the correct size and design of UPS for your requirements.

All uninterruptible power supplies use stored energy to maintain power to the load when the mains supply fails. The power flows through a unit in different ways, depending on the type of UPS system.

The length of time that a UPS will provide critical backup power ultimately depends on the capacity of its batteries and the load that is connected.

There are three primary types of UPS:

  • Online UPS/Double Conversion UPS
  • Line-Interactive UPS
  • Offline UPS/Standby UPS

Here’s a brief explanation of how each type of UPS system works.

Online UPS

Also known as double conversion UPS, an online UPS offers efficient protection against complete power loss and a range of other power problems. It provides a high level of security and is the best option for mission-critical equipment.

An online or double conversion UPS takes the input AC (Alternating Current) mains and supplies a rectifier which then converts this AC source into DC (Direct Current). The batteries are then usually connected to the DC bus created by the rectifier. Charging of the batteries can be done directly via the DC bus or via a separate DC Charging circuit.

The DC supply from the rectifier supplies the Inverter section so that the load is always protected by the inverter and thus maintains a constant output supply regardless of the mains input voltage. Whilst the inverter tracks and synchronises its output waveform to that of the incoming supply the output voltage and frequency are maintained at a constant preset value. The ability to synchronise with the mains allows the UPS to switch from inverter to mains supply seamlessly in the event of a fault, overload or for maintenance purposes.

In the event of a mains outage the DC Bus and inverter are supplied directly from the batteries without any break in output supply.

The conversion from AC to DC and back to AC offers the best protection from all mains deviations and is where the term double conversion is derived.

Line-Interactive UPS

In a line-interactive UPS system, the inverter is always online. This type of UPS is especially effective in situations where complete power failure is rare, but fluctuations are common.

A line-interactive UPS always keeps the inverter online and simply switches from charging mode to battery power in the event of a power failure.

With this topology, the UPS inverter is always online and thus the protected load benefits from a constant preset output voltage. When the input AC power (mains supply) is within tolerance, the UPS inverter acts in reverse and can charge the batteries.

If the input power fails, the transfer switch will open and the power will flow from the battery, through the inverter to the UPS load. A line interactive UPS also incorporates an automatic voltage regulator (AVR) which utilises transformers to either boost or reduce the incoming supply should it fall just outside of the preset input tolerances.

This feature prevents the batteries from being discharged when the input source is unsteady or unreliable but only slightly outside of an acceptable voltage window. There will also be additional filtering and there is no break in output supply in the event of a mains disturbance as the inverter is always connected to the critical load.

Offline UPS

Offline UPS systems, also known as standby UPS, pass mains power directly to the load during normal operation. The UPS monitors the incoming supply and activates the inverter should the input fall outside preset voltage or frequency tolerance windows.

In an off-line or standby UPS system, the critical load is powered directly by the utility or mains power during normal operation.

The UPS monitors the incoming supply and the inverter, which is supported by a battery system, is only activated once the input voltage falls outside of preset voltage or frequency tolerance windows.

There is a very short break in supply (typically 2-3 mS) while the inverter transfers online. This break in power is fast enough that almost all electrical and electronic equipment supported will continue to operate unaffected.

The UPS incorporates a surge suppressor and in-line filter to condition the mains supply fed to the load although any variations in input voltage and frequency are not adjusted.

Always Worth Speaking to an Expert

There are several factors to consider when choosing which UPS system is right for you. Power capacity, size, form factor and, of course, price should all be considered. Which type of UPS is most suitable for your needs is also a key factor, so we always advise to call us to speak to an expert to get the right UPS.

We provide unbiased advice on the best solutions for your back up power requirements. Working with leading manufacturers, our product portfolio incorporates all the latest, energy efficient technology available with the best customer service from an experienced team of UPS experts.

Our range of online UPS, line-interactive UPS, and offline UPS products are designed using the latest technologies to deliver reliable back-up power. With a selection of single or three phrase UPS systems from 400VA to 6.4MVA, rack tower or modular designs and battery runtimes available from a few minutes up to several hours, we can deliver secure critical power in the most energy-efficient way.

Give us a call today on 01234 851155 to speak to one of our UPS experts and find out how we can help you with your critical power backup.

Adam Baverstock

Sales Director

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