Suggestion for selecting UPS

Hi Monirul :) There are alot good brands who make UPS and one of them is APC which is considered the best (so far in my country) also UPS and PSU are the real combination and everything else in the server and it's components comes second. The thing you talking about lower voltage problem is called the Voltage Regulator which comes built-in in newer UPS and it maintains the high/low voltage and also pure sine wave is important too. Also the Transfer Times of both UPS and PSU is very important when there is fluctuation problem in electricity or black outs. The Transfer Time of a UPS should be less than the time of PSU i.e. UPS = 10ms and PSU = 17ms (on peak loads) this info can be found on the official link page of the products or on the Box and Booklets of them.

Monirul said:

...please suggest me, which VA UPS (300 VA or 600VA) I would used...

At a minimum you need one that will run your system long enough to let it shut down gracefully when the battery is dead. If you have a fully loaded gaming system you're going to need more juice than a barebones Internet-only computer. My experience has been that the time estimates from the manufacturer are the best-case scenario.

My advice would be to choose the biggest one you can afford, then borrow money from all your friends and get one that's even bigger.

Monirul said:

Thanks Mr. Boogieboy for your reply. So you want to say, the latest UPS is capable for Voltage regulator. If I use a latest UPS, then I no need to think about over voltage and lower voltage problem. The UPS is capable for control that problem. If it is right then please suggest me, which VA UPS (300 VA or 600VA) I would used.

Thanks

Exactly the newer UPS's are capable of controlling the voltages and it will be printed on the box of products as well :) Also one more thing is not to mix the VA with Watts for example 1000VA = 670 Watts [this is according to APC site and seems like they used 0.67] (Power Factor) different manufacturers use different multipliers sometimes and usually on the internet some use 0.75 or 0.8 (1000 x 0.8) to measure the max output of the UPS. If you calculate 600VA x 0.8 = 480Watts. You can do the math for the rest :) like profdlp said it's always better to get the bigger one. Also please let us the know about your Power Supply Watts? Hope it helps.

Have you checked in Control Panel >> Power >> Advanced and made sure you have it set to Sleep or Hibernate in the event of power loss? Does it use a USB connection so the computer knows it is there?

Monirul said:

Thanks Mr. boogieboy for your reply and again thanks for your helpful information. Currently I using "Powerguard" UPS which is 1200VA. And my power supply watt is 750 watts. But this UPS is don't backup at the time of power failure. I checked my UPS by a technician. That is ok. If I divided it by (.8) then I get output is 960 watts. But my PSU is 750 watts. So where the problem. Why it is dont give backup.

Thanks.

Please also tell us what other components have you attached to the UPS? Monitor? if yes what type of Monitor are you using is it a LCD or a CRT Monitor and what size? How long have you been using this UPS? Hope the components are'nt overloading the UPS at the time of Power-Failure.. usually the 750Watts PSU is'nt running at it's peak power unless your running a heavy 3D application.. Let us know the specs of your system and the component your using with the UPS :) than we'll try to point out the problem that might be causing the trouble.