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Online UPS Systems

A range of online uninterruptible power supplies designed to protect critical IT servers and networks and provide the ultimate form of uninterruptible power with a digitally generated sinewave output supply, the ability provide back-up for long duration runtimes and a built-in automatic static bypass. Online UPS can be single or three phase, with online three phase systems capable of running in parallel/ redundant (N+X) configurations for added resilience and scalability. Online UPS provide protection from spikes, electrical noise, brownouts, sags, surges and sudden power outages and power cuts. As the inverter section is rated for continuous running online systems are used for long battery backup times up to several house.

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Online UPS v Line Interactive Power Protection

This type of uninterruptible system is classed under IEC EN62040-3 as Voltage and Frequency Independent (VFI). The UPS inverter constantly powered and connected to the load during normal operation protecting the critical and essential loads from outages and power problems. This type of unit provides the highest levels of protection. The inverter generates a sinewave output which is tightly regulated, in terms of both output voltage and frequency.

As the UPS constantly supplies the load, there is no break in supply. The conversion process is most commonly a double conversion (AC-DC-AC) or triple conversion (AC-DC-DC-AC). The UPS is connected to the local AC (alternating current) mains supply (or generator) through a built-in rectifier/converter. This converts the AC supply to DC (direct current) to charge the battery set and supply the inverter section. The inverter section requires a DC input, either from the connected battery set (which may be lead acid or lithium-ion) or the rectifier/converter and provides an AC output to the connected load.

An on-line system also features a built-in automatic bypass. This provides safe failure to the mains supply should the system be overloaded or develop an internal fault condition. As the inverter is rated for continuous running, this type of product can be used for long runtime applications. Additional battery packs are connected, either plug-and-play or hardwired. Runtimes up to 7hours or longer are possible with extra batteries.

This type of no-break technology is typically sized in VA (Supply Voltage x Amps) or kVA (=1000VA) or kW (=1000W). The model range includes both single phase UPS and 3phase UPS output solutions with configurations including input/output: 1/1, 3/1 and 3/3. On-line UPS can run from less than 1kVA to 1MVA or greater allowing the technology to be used to supply small applications to large data centres and industrial manufacturing sites.


Several UPS accessories are available for this type of system. These include communications interface cards (SNMP and Modbus for example), UPS maintenance bypasses (wall and 19inch rack mount) and PDUs.

Maintenance Bypass

A maintenance bypass allows the system to be bypassed and safely isolated for a service engineer to work on the system during a preventative maintenance or emergency response visit. The bypass also allows the system to be removed and swapped out, should this be required, without disruption to the critical loads. Larger UPS may have a built-on maintenance bypass but for a UPS maintenance contract an external bypass is recommended. For larger installations the bypassing arrangements may include interlocking and signal contacts for remote reporting to a building management system (BMS).

Battery Replacement

The batteries most used in these double or triple conversion systems are valve regulated lead acid with a 5year design life and under normal conditions will requirement replacement in years 3-4. The ideal room operating temperature for this length of life is 20-25degrees Centigrade. For every 1degree rise above 30, the design life halves. 10year lead acid batteries are available for some systems and for larger models may be offered as standard. Lithium-ion battery systems are also available.

When the batteries require replacement, Server Room Environments can provide battery replacement sets for you to fit where the batteries are user-replaceable. We also provide a battery replacement service. A full eco-friendly battery disposal service is also available to ensure materials are reclaimed for later usage.

Input and Output Connections

Up to 3kVA the products have plug-in cords. In the UK these have a BS-style 3-square pin plug. Output from the system is made using C13-C14 cords. At least one cord is supplied with each product. Additional cables can be purchased as required. We also supply an IEC socket strip. This connects into a UPS outlet socket and provides 4x UK style socket outlets. IEC C13/C14 socket outlets are rated at 10Amps, and it is important to ensure that the connected loads do not overload the connected outlet. The UPS may also provide a load shedding functionality. Above 3kVA the device will have hardwired input and output connections and may offer additional 16A C19/C20 or 10A C13/C14 outputs. Hardwired connections must be completed by a suitable qualified electrical contractor or electrician to comply with building and electrical regulations.

Management and Communications Interfaces

Each UPS has a communications interface which can include USB, RS232 and/or a plug-in communications card slot. The most commonly installed comms card is for SNMP. This allows the UPS to be connected to the local IP network. Once connected to a computer or network, UPS monitoring and control software can be used to display important information including load and battery status, and initiate an orderly shutdown of the protected computer or server(s) before the battery is exhausted during a power outage.

Powering Critical Business Applications

These systems are vital for critical business applications and those in industrial environments. The grade of protection offered is higher than can be achieved from an interactive UPS. Industrial systems are designed for harsh environments with higher case IP ratings, fan filters and isolation transformers.

Project Management

Server Room Environments provides a complete project management service. We can carry out a site survey to identify all the related shipping and logistics costs, review the electrical works to complete your installation and provide a project price including post installation support and maintenance contracts.

Available models and brands from Server Room Environments include APC by Schneider, Borri, CertaUPS, Eaton, Riello and Vertiv.


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