Guarding against power failures is essential in mission-critical environments, and local servers and network storage systems in corporate branch offices often need to be protected just as much as those in central datacentres.

The MGE Evolution S 1750 is a 2U rack-mountable uninterruptible power supply (UPS) designed specifically to protect servers and other network equipment in these environments. It is rated to 1,750VA, which means that it can support up to eight systems with a combined power rating of 1600W, though the more devices that are attached, the less time the fully charged battery will last.

Alongside the eight power output sockets arranged in two banks of four, the rear of the device sports a standard 230W power input socket, USB and RS232 communications ports. There is also a socket that recognises the connection of an additional battery supply, allowing up to four UPSs to be joined together to provide extra backup power in the event of mains failure.

The unit we reviewed came with a hot swap maintenance bypass (MBP) unit that allows administrators to replace the UPS without disconnecting attached devices, simply by switching the loads to the mains supply while the UPS is replaced. The MBP supplied features three standard female AC power sockets and comes with two heavy-duty power cables for connection to the UPS.

As well as being rack-mounted – a pair of slide-in brackets are provided for this purpose – the unit can also be used as a standalone device, with two screw-on stabilisers allowing it to stand upright on a flat surface.

The UPS we reviewed came with a network management card that slots into an aperture on the back of the unit, featuring a 10/100 Ethernet port and RS232 port for connection directly into either the LAN or an environmental sensor. We installed the network management card and connected an Ethernet cable to our switch, but the network could not find the device when we tested it.

Power management software was supplied on CD, and an A4 installation and user manual plus a quick-start leaflet provide detailed instructions on how to set up and utilise the UPS. We had to download the latest version of the Solution-Pac 2 management software from the MGE web site, but were unable to test it because no attached UPS was recognised. When it works, it provides the ability to remotely shut down network servers, according to MGE.

The Evolution UPS family is line-interactive, which means it can stabilise and remove minor fluctuations such as line noise, frequency variations, line spikes, and brownouts from the power supply, as well as keep the battery charged and quickly switch over to battery

backup should the AC mains be interrupted. On the downside, line-interactive UPSs can use more

electricity because they are continuously charging the battery to replenish the electricity used by attached devices.

The device fan is quite loud in operation, particularly when the battery is charging, but this should not be a problem in already noisy computer rooms.

LEDs on the front of the device indicate whether the load is protected, unprotected or running in downgraded operation.

Two lines of LEDs indicate the battery charge level and the percentage load (25, 50, 75 and 100 percent), while a couple of others indicate whether either or both rows of connected devices are being supplied with power.

We ran the UPS for about a week, periodically turning off the power for between five and 30 minutes. Each time, the two servers we attached to the device remained functional, did not reboot and no disruption was caused to normal operations or running applications.

The Evolution S sends out audible alarms to indicate the mains is off and battery supply activated, and the frequency of the alarms increases the closer the battery gets to being drained.

We deliberately ran the battery down to get some idea of its capacity. UPS battery life always varies according to how much connected equipment is being supported, but in our case both servers remained active for one hour, four minutes and forty-two seconds before the battery ran dry.