UPSD - Uninterruptible Power Supply Devices
A.M.F.
amfilip@public.srce.hr
electrical 


1.	INTRODUCTION

Occasionally even in the most developed countries power 
blackouts occur. Today, power blackout is very common 
appearance, and the voltage quality is not at envious 
level. Because of that, usage of an UPS device should 
be an interesting option. Computer users usually know 
the components of which the computer consists from, but 
very small amount of them knows that for the correct work 
of these devices quality AV 220V and 50Hz frequency is 
reqired. Here are described the advantages of an UPS 
device and dangers from which such a device protects us.


2. VARIETY OF DANGERS

2.1. Voltage spikes

	They occur as a thunderbolt strike consequence 
in shape of very short voltage jump whose amplitude goes 
as high as thousand volts above the default net voltage. 
They can, without problems by passing through the 
socket cause great damage inside the computer. 
Experience has shoved that the most efficient voltage 
spikes removers are net interactive UPS devices 
whose working principal is ferroresonancy. Produced 
damages don't have to be visible instantly (writeable 
media overmagnetisation), but of course can 
(integrated circuitry burnout).


2.2. Voltage strikes

Short time duration voltage strikes whose power is few 
hundered volts higher than default net voltage occur 
when a device which is great net current consumptor is 
turned on or off. Damage that is caused is similar to 
the one caused by voltage spikes. Long and frequent 
voltage strikes can cause nonnegligible damage to the 
computer equipment.


2.3. Voltage dilapidation

They are just the opposite to voltage strikes. Typical 
voltage dilapidations are in 20% margin below the nominal 
socket voltage. They can significantly damage the computer 
and cause computer to block. Sudden voltage dilapidations cause 
momentary erasation of informations content which are stored 
in computer memory. Momentary dilapidations of net voltage 
have negative affect on both hard and floppy disk drives.



2.4. Subvoltage

Subvoltage is longterm state of low net socket voltage 
(15% below nominal value). Cause are malformations in 
distributive net. Consequences of subvoltage are visible 
on all computer components. Informations vanish from memory, 
hard disk is rotated with less RPTU and picture displayed on 
monitor is flickery. Proposed solution is purchase of an UPS 
device with enough battery capacity.


2.5. Harmonical distortions

They occur during work of impulse current consumptors. Such 
devices are xerox machines, telefaxes and motors with 
regulable RPTU. Connection of an nonlinear consumptor 
to the same socket as computer could cause various 
irregularities in computer's work. For right UPS device 
choice it is good to know input-output voltage and current 
distortion's of that UPS device.


3. CONCLUSION

Every computer user should consider buying an UPSD, because 
it can pay itself out during just one stormy night. And, 
when you think over they are not so expensive at all 
($270 ÷ $1300), considering that they can save vital 
parts (if not all) of your computer. At the end, I would 
like to recommend some manufacturers to help you find 
the right one for you: "Best Power", "Victron", "MGE 
UPS Sytems" and "APC".