Return To 12/95 Prototype Edition Index
Traditionally, well for the last year or so, the purpose of smaller UPSs on individual computers or small networks; has been to hold the power up after a mains failure, to enable an orderly shutdown of the computer.
It has also been traditional to support only the computer box and monitor and allow the printer and other peripherals to crash when the mains failed.
This made some sense when printers were power hungry and slow; and the additional cost of a bigger UPS was not acceptable.
But things are changing...
UPSs have come down in price - especially the smaller off-line types. Printers are faster and less power hungry. There is more communications going on - both via modems and in-office networks.
Computer tasks are more likely to involve movement and storage of larger amounts of bytes. Newer tasks in graphics and multimedia cannot easily be closed down until they are finished. Tape backing-up is increasingly in use; it is fairly slow, and most irritating to have interrupted.
What to do...
Types of UPS
The lower cost off-line (sometimes called standby) UPSs are fine for most applications. However they are not available for much over 1000VA (equivalent to about 700 watts) of power. Also they do not usually allow extra batteries to be attached to increase the support time.
One trick is to use a bigger UPS than you need to get more support time. For example a 1000VA at full load might have a support time of 10 minutes, but at half load (500VA) you would get not double the time but nearly three times.
On-line types are more expensive, but most makes do allow extra battery packs to be connected, and they are available up to very high powers.
If in doubt... There are plenty of UPS - literates around who can advise.
John Stevens graduated in Physics from London University and spent many years in electronic product development and management. Return To Text
His company, UPS Surveys, specialise in UPS sales and support, as well as computer manufacture.
