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[|DRC| Wartex]

Intro

I bet the following happened to you: you were typing your work or school papers, a long email, forum post or just playing your favourite video game online, suddenly lights dimmed for a second and computer restarted! Oh no - all of your work is lost!
You are frustrated because you didn't hit "Save", or you buddies finished the game without you while you were restarting your computer. This can be very frustrating, not to mention it can cost you time and money.

Computer is very sensitive to power changes. While a modern computer power supply has means to suppress power surges it has no way to prevent brownouts or power outages.


There are nine common power problems that UPS units are used to correct:

Power sag - Short term under-voltage, for example when your neighbour starts his power-hungry circular saw.
Power surge (spike) - temporary increase in power level, for example due to lightning striking the power lines.
Power failure (outage, blackout) - long term loss of power due to damaged power lines or malfunctions in power grid. While they seldom happen, they can happen repeatedly during storms. While you should not generally use your computer during lightning storms, sometimes it's critical to complete something and power outage may kill hours of work.
Under-voltage (brownout) - Low line voltages for an extended period of time, for example when a tree touches the power line and some power leaks into the ground.
Over-voltage - Increased voltages for an extended period of time.
Line noise - distortions superimposed on the power waveform.
Frequency - variation of the power waveform.
Switching transient – under-voltage or over-voltage for up to a few nanoseconds.
Harmonic Distortion - multiples of power frequency superimposed on the power waveform.

There is a number of destructive ways surges, sags, brownouts and outages can affect you as a PC user:

The most common:
* Lost work, time or money due to unexpected PC restart/shutdown.
* Ruined online gaming experience.
* Damaged connected equipment (for example, your printer is designed to withstand power surges coming through it's power cord, but not the cable that is connects it to your PC!)

Ruined hardware, storage media or file corruption during a write/burn process:
* CD/DVD disks ruined while being burned.
* Network router, flash MP3 player, digital camera or motherboard damaged during firmware update.
* Corruption of files on external drives or USB flash drives.
* Corruption of memory cards from your digital camera while in your PC card reader.
* Damage to your RAM chips leading to unexpected restarts or BSODs ( blue screen of death ) in the future.



A UPS can save you!

An uninterruptible power supply, or UPS, (sometimes called an 'uninterruptible power source ') is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a battery when utility power is not available. A UPS is inserted between the source of power (typically commercial utility power) and the load (in this case, your PC) which is to be protected. When a power failure or abnormality occurs, the UPS will effectively switch from utility power to battery power. The transition from utility power to battery is instantaneous and therefore constant, non-interrupted power supply is maintained to your PC, saving you from all the troubles I described above.

Buying UPS is the best thing you can do for your PC and yourself, because a power bar with surge protection is not enough!



Frequently Asked Questions

Q: Ok, after all this wonderful stuff I read about UPS, how much am I going to shell out for one?
A: For an average home PC a new UPS will cost you between $50 and $150 (USD). If you have a gaming or multimedia system, you are looking at $100 - $250. If you are running a multi-processor business server, aim for $250 and up to $10,000 or higher. You would only need such a large UPS this if you have a server farm of 100+ computers.

Q: Where can I buy one?
A:
Wal-Mart
Home Depot
Staples/Business Depot
RadioShack/Source
BestBuy/FutureShop
www.newegg.com
www.tigerdirect.ca
...local computer stores and pretty much anywhere computers are sold.

Q: What's the lifetime of a UPS?
A: It depends, UPS itself will last 10-15 years, but the battery in it is good for about 3 years given you have no more than 20 power surges/brownouts and 5 power outages (leading to full battery discharge) per year. If you are worried whether your investment is sound, $69.99 UPS over 3 years is about $1.90 a month. Given that by using UPS you "insure" against lost time, damaged hardware, memory cards and valuable files, $1.90 a month is a great deal. Most UPS manufacturers provide real insurance (usually included with UPS) for connected equipment, with premiums from $10,000 up to $150,000.

Q: Ok, so how long will the battery last when the power goes out completely?
A: For UPS designed for desktop PC, while the box will claim it will last XX minutes, the actual value is about a fifth of that. For example, if you buy a 650 VA UPS (650 VA is a capacity of a UPS. The higher the number the longer it can supply power using it's battery), the box will most likely say it will last for 50 minutes. This is true if you connect a 100 watt table lamp to it. If you connect a modern Pentium 4 system with a 19 inch monitor, battery will last for about 8-10 minutes, which is more than enough to save your documents, finish burning a CD or DVD, cancel file copying to/from your memory card and safely shut down the computer. Most UPS come with software that will automatically save documents and shut down your PC in case you are away while power goes out and the battery is about to die.
Tip: if your computer already started shutting down but does it slowly, turn off the monitor so you can get more runtime.

Q: How does UPS shut down my computer?
A: It connects to your computer with a USB cable, and uses it to send save and shut down commands to UPS software running on your PC, as well as information about utility power line conditions, history of power anomalies, remaining battery charge etc.

Q: Can I connect everything on my table to my UPS?
A: No, UPS can only produce a limited power output while running on a battery, and is intended for controlled shutdown rather than continuous support. It's capacity and power output rating is written on the box or in the manual.

Q: How do I get the correct UPS for my system?
A: Typical 650 VA UPS is rated 350-400 Watts, which should be sufficient to run a modern gaming PC for about 5-15 minutes off the battery. The connected load typically should not exceed 80% of either UPS rating.

You can use the following tools:
APC UPS Selector http://www.apc.com/tools/ups_selector/
Belkin's UPS demo http://www.belkin.com/avr/
Tripp Lite Selector http://www.advizia.com/tripplite/


As a general guideline, to find out what bare minimum VA you need, use the following rule:
Pw = your computer power supply wattage (should be on a sticker on your PC power supply, you might need to open the PC case [not the PC power supply itself!!!] to see it)
Pm = monitor power consumption (should be on a sticker the back of the monitor). If unknown, assume 100 if you have an CRT monitor or 60 if you have a flat panel (TFT/LCD).

VA = (Pw + Pm), basically sum of power rating of PC power supply unit - PSU (don't confuse with UPS) and monitor
This formula may seem strangely simple to tech-savvy people, I explain it the following way:
Wattage is about 65% of VA (volt per ampere) for dynamic loads sych as PC (or conversely, VA is 1.54 * Wattage). Properly built PC should not exceed 65% of it's PSU capacity when working normally. So we have: VA = (Pw + Pm) * 1.54 * 0.65 = (Pw + Pm) * 1.
For a 400 Watt computer power supply and a 100 Watt monitor, you need (that's bare minimum) a 550 VA UPS. 550 VA UPS is rated 350 Watts, so we have 350 - 100 w monitor = 250 watts for a PC.
Example: Pentium 2.8 Ghz CPU dissipates 60 W + 20 W HDD + 20 W DVDROM + 15 W motherboard + 7 W sound card + 9 W network card + 70 W video card + 10 W fans = 211 watts. This setup will not overload the UPS.

Q: How many outlets does UPS have?
A: Generally, they have 6 to 10 outlets, half of which are battery backup and the other half is filtered power (surge protected but NO battery backup). Some UPS also have jacks for cable, telephone and ethernet surge protection.
Mine has 6 outlets, I use battery backup outlets for PC, monitor and my cable modem. 3 others I use for printer, digital camera power adaptor and cell phone power adaptor.

And yes, this post was typed on a UPS-protected pc

Portions taken from WikiPedia
http://en.wikipedia.org/wiki/Uninterruptible_power_supply
http://www.jetcafe.org/~npc/doc/ups-faq.html
http://www.uninterruptiblesolutions.com/index.php?main_page=faq

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[|DRC| psycheus]

Awesome write up! Thanks Wartex!
_________________
psycheus.com
tacnit.com

[|DRC| Iceman]

One of these days I will get around to buying one