Uninterrupted Power Supply (UPS) - Backbone of Your Small Business
By Michael Russell
A UPS device is normally bought as an afterthought, if any money is left after
buying the PCs. But a UPS not only keeps work going in case of a power cut, but
also protects machines as an advanced surge protector and a device that provides
clean power supply essential for a PC. All this comes at just a small price, but
ensures that your valuable investment stays safe.
Calculate your power needs. This is the tricky part. No matter which UPS
(Uninterrupted Power Supply) company you approach, it would want to sell a high-
end solution for your home office or small business, while you will be better
off with a solution that is much more attuned to your needs. Before purchasing a
UPS you need to consider your PC's power consumption.
A regular Pentium 4 computer with a generic 17-inch monitor consumes close to
400W or 560VA (Volt/amps) of power. We will assume this consumption if the
configuration has a single hard drive, 256 MB of RAM and a Combo drive. No
printers or other external power consuming equipment have been considered.
In such a situation, it would be wise to go in for UPS with 600VA rating. Also,
a UPS falters if the load on it exceeds its rating. So if a 500VA load is
applied on to a UPS that provides 500VA of power, you will end up getting only
five minutes of back up time. Based on this thumb rule, calculate the VA rating
for each device you want connected to the UPS.
Here's an easy way of calculating the VA rating for each device that you have:
1. List all equipment you want connected to the UPS- monitors, hubs, external
hard drives, in fact anything that requires power and needs protection.
2. If any device has a power rating given in watts, take that figure and
multiply by 1.4. This gives you the device's VA rating.
3. Check the amps and volts ratings of the devices you have listed. To get a VA
rating, multiply the amps by the volts.
4. Add the VA ratings of all your devices to get a grand total.
5. Multiply this total by 1.2 if you want to factor in one more device later.
6. Make sure that whatever type of UPS you opt for, your VA total should not
exceed the VA rating of the UPS. It is always recommended to buy a UPS with a
higher VA rating than your cumulative VA rating.
Before you set up...
SoHo (Small Office Home Office) businessmen would typically face two scenarios
when it comes to UPS implementation - whether to connect one big UPS to centrally
control all PCs at the same time, or to have individual UPS for every PC.
Why only PCs? Because connecting a printer (especially if it is a laser printer)
to a battery output socket on the UPS will cause considerable power drain, which
could instead be used for another PC.
Based on our power calculation earlier, a modest eight-person SoHo outfit would
require at least a 5kVA UPS considering eight Pentium 4 PCs with 17-inch
monitors. This done, check the UPS type you consider to be the best option in
your budget. We would recommend spending a little more and get a good UPS rather
than go for an "in-the-budget" solution.