An uninterruptible power supply, best known as simply a UPS, is a battery device that keeps a computer running should its main power source be lost or in the event of a power surge. While some options come as standard on a UPS, others may only be available on request. Here is a breakdown of some of the various features that can make up a UPS.
1. Galvanic isolation
This feature provides the opportunity to separate the mains supply and the output supply. This is normally required when there are high levels of spikes and electrical noise on a site (see http://www2.nationalgrid.com/uk/services/land-and-development/grantors-and-land-owners/noise/).
To achieve this neutral pathway, a transformer is usually present but housed separately.
2. Harmonic filters and rectifiers
Small UPSs, up to 10kVA, usually do not generate harmonics to the mains supply. Larger UPSs with a 6-pulse rectifier, however, do, so the way around this to install a harmonic filter cased in a separate cabinet or put in a 12-pulse rectifier to replace the 6-pulse one.
The release of harmonics can prevent synchronisation of UPS devices to a generator supply and pollute downstream hardware.
3. Communication methods
-Front panel LED
A front panel LED is a good way to indicate if there is a status alert, and can even be fitted even into small single phase UPSs.
An alphanumerical panel can equally provide pivotal information on the UPS, mains and battery and can, at times, store historical data and logs while allowing for customisation.
The most common conditions to monitor are load, battery and charge percentage as well as runtime available and mains voltage.
If there is no access to a front panel, remote communication can offer operational, diagnostic or historical data.
There are many types of UPSs that can be purchased, with Eaton UPS a popular model (see http://www.cppsales.com/).
A UPS can be interfaced with a voice and data system which notifies users of changes in any operating measures, thus enabling orderly shutdowns when required.
Serial communication can be achieved using serial lines with twin or pair connection. These include RS232, RS422 and RS485.
Finally, you can choose a UPS which is managed by a Simple Network Management Protocol (SNMP), achievable with hardware or software solutions and able to assist with network-wide management.