What Are the Different Types of UPS Systems?

An uninterruptible power supply (UPS) is a source of clean electrical power that is stable, and readily available in the case of a power outage. It can generate 110VAC required to power equipment for a limited period until the grid power is restored.

A typical uninterruptible power supply includes a battery that provides critical backup power. The rest of the conversion from the battery to AC power is done by an electronic voltage converter. In addition to providing backup power, a typical UPS also protects your equipment and peripheral devices from damage due to bad power quality, lightning strikes, etc.

 All three basic uninterruptible power supply (UPS) technologies have their place in protecting today’s distributed IT infrastructure especially on the network edge. Each technology has its advantages and each may be necessary for configuring cost effective power protection, especially in complex systems.

Selecting a UPS for your particular application requires an examination of a number of factors. The load size, location and criticality of the equipment to be protected are key, as well budgetary considerations, when choosing a UPS for power backup.

Types of Uninterruptible Power Supply Systems

There are three main types of uninterruptible power supply systems, defined by how power moves through the unit:

1. Offline/Standby/Battery Backup

An offline UPS also called a standby UPS, is the simplest and most affordable option. It typically stays “asleep” while the system uses wall power. When wall power fails, an automatic transfer switch starts to pull power from the UPS instead. When the AC power from the wall returns, the transfer switch reverts to wall power and the UPS goes back to sleep.

These systems can offer battery backups and light surge protection with high efficiency. While an offline UPS will switch on within seconds, it doesn’t provide the instantaneous transfer that many electronics require. It may offer more limited protection, but it’s a good choice for low-power devices such as computers or office equipment.

2.  Line-Interactive

With line-interactive UPS, the inverter becomes part of the output and is always on. The inverter can operate in reverse to charge the battery while AC input is normal, and switch to battery power when input fails, which provides filtering and voltage regulation. Line interactive UPS systems rely on the battery to condition power so this type tends to drain its battery more frequently than online UPS systems that condition power through the double-conversion process.

When AC input power fails, the unit’s transfer switch opens and the power flows from the battery to the UPS output. With the inverter always on and connected to the output, line-interactive UPS provides additional filtering and yields reduced switching transients when compared to a standby UPS. Line-interactive UPS systems are typically used in rackmount applications below 5000VA.

3. Online or Double Conversion UPS Systems

AC power is stable and clean upon generation. But during transmission and distribution, it is subject to voltage sags, spikes and complete failure that may interrupt computer operations, cause data loss and damage equipment. When it comes to safeguarding critical IT loads, only online double conversion technology protects fully against all these power problems, providing the highest levels of security for networks.

An online UPS system is usually called double conversion as well because incoming power is converted to direct current (DC) and then converted back to AC. This AC-DC/DC- AC design ensures an increased degree of isolation of the load from the irregularities on the main supply.

The online UPS takes the incoming AC power supply and converts it to DC using a a rectifier to feed the battery and the connected load via the inverter so that no power transfer switches are necessary. If the main AC input fails, the rectifier drops out of the circuit and the batteries keep the power flowing to the device connected to the UPS. When AC input power is restored, the rectifier resumes carrying most of the load and begins charging the batteries.

Because power runs through an online UPS continually, output is a perfect sine wave. This type of UPS protects the critical load from virtually all power disturbances, including subtle harmonics and waveform distortion.

This means the quality of power from online UPS is significantly better than that of other technologies. Offline and line-interactive technologies reduce the impact of spikes, surges and sags by either clipping the peaks and valleys, boosting power or switching to battery backup. Within the normal track of an electrical sine wave, however, most power fluctuations are left alone. Online UPS regenerates the sine wave, not just conditioning of the raw utility supply.

What are the benefits of an uninterrupted power supply?

There are several benefits of using a UPS system:

1. Reduced downtime: A UPS system can keep your equipment running during a power outage, allowing you to avoid costly downtime.

2. Improved equipment protection: A UPS system protects your equipment from power surges and spikes, which can damage sensitive electronic components.

3. Peace of mind: Knowing that your equipment is protected by a UPS system can give you peace of mind in the event of a power outage.  It allows you the flexibility of safely shutting down your systems in the event of a prolonged outage in the event power will not be quickly restored or an additional power source such as a generator is unavailable.

4. Better energy efficiency: Some UPS systems include features that can help improve your energy efficiency, such as voltage regulation and battery management.


Uninterruptible power supplies provide your business with security and reliability in the case of a blackout or power outage and will protect electronic equipment from damage or data loss. At Hubtech Limited we have a variety of UPS ranging from Apc, Mecer, Mercury and tripplite.

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