Corsair Psu Query!!

[BULLZI]

Hi guyz,

I own a HX 620 Watt psu. I was using my system without any UPS for 5-6 months. Recently I bought an APC 1000 VA Back UPS.

Last Saturday nite, I turned on my system and within 5 minutes, my UPS turned on red indicating overload and change battery simultaneously and turned off. When I again turned on the UPS, I blew out the entire electricity phase of my house.


I suspect a short circuit and probably the spike board I am using is the culprit. But after changing the board, the problem still persists. This time I noticed a spark inside the psu and again total electricity gone . Rite now I am feeling quite afraid to turn on my system :.



I checked with an electrician and he said everything was ok with the electricity line. Then I guess its problem with the psu.

Just before going for an RMA, I need your advice.

1) Is it possible that the psu suddenly got a short circuit connection inside it?
2) Am I going to get an RMA for this type of problem?
3) How to check that the UPS is well and good?
4) Is there any fear of my CPU components being damaged?

Please help me out. I need some quick advice as I cant do anything with my system until and unless this weired thing stops happening.

Thanks.

[BULLZI]

Please guyz, give some suggestions so that I can do accordingly.

[sagargv]

1) had happened once with a local 300W psu for me and there was a spark coming out of the psu .. i cant believe that it happened to corsair hx620W
2) difficult to get RMA for blown components AFAIK.
3) dont know .. u could try using the ups on the TV or find the voltage using a multimeter
4) when the smps had blown like fireworks for me ( local one , 3 yrs back ) , nothing had happened to cpu and other components ..in forums , i've read several times that psu burnt like fireworks but people have never complained that their components also went poof .. so , i think there are quite less chances that u've damaged ur cpu/mobo etc.. .and along with that ur psu will have super protection systems which will have most likely prevented damage of the cpu/ mobo etc. .

[BULLZI]

But I havent blown my psu. Its not at all my fault. I didnt do anything heroic using my damn good psu

.

[nish_higher]

eDIT- u might get RMA or if not get it serviced locally

[adithyagenius]

@bullzi
how much did you 1kva ups for?

[BULLZI]

^
@6500/-

[adithyagenius]

thank you
please post if your problem with psu and ups gets solved because I too am also planning to buy the same combo.
1) did this happen when you connected the psu to ups for the first time or was it running fine with the ups and out of the blue one day it blew?
2) have you isolated the problem to psu by making sure that ups is not at fault? see if you ups can handle tv and monitor.

[adithyagenius]

I typed this in the previous post but deleted before posting because i was unsure of the info. I have confirmed it and its because of active pfc of your psu. PFC stands for Power Factor Correction. To understand power factor you need to do a basic course in electrical engineering. I am having that subject in this semester. Your psu is incompatible with your UPS. APC UPS is pseudo/simulated sine wave generator. Active PFC is meant to work with true sine wave. Buy APC's true sine wave generating UPS. I think its APC SMART series. hope this helps. Please reply to confirm if this worked because I am planning to purchase a psu with active PFC and also a UPS.

[BULLZI]

Hey thanx for the info.

Actually I heard that APC 650 VA was not compatible with my psu due to that sine wave problem. Hence, gone for 1000 VA. But still ......

[adithyagenius]

I just checked that APC smart series has sockets which dont work with india plugs and they are damn expensive.

[BULLZI]

Please provide me with some links if u can

[Big-G]

So what all are the options for an owner of Corsair PSU 620 W or as a matter of fact any PSu with active PFC.

1. One can use his smps without the ups and it's safe else he'll end up like bullzi .

2.Opt for a power supply which doesn't features the PFC .

3.Purchase an expensive true sine wave genrating UPS , if it exists or do with make shift sine wave genrators .I really wonder if it's even theoritically possible to genrate an absolute sine wave with all it's crests and troughs.

is semester waalay genius Electrical Engineer saab could this issue be due to the fact that the 1000VA UPS is not compatible wrt to the power it can handle , I mean 1000VA translate to 600Watts as per APC ie that is the max load it is rated for and the smps is rated for a higher wattage of 620 Watts .

I know the smps would never be drawing 620 watts on a normal system , but may be it draws it's rated wattage ( AC) and converts only the required wattage into DC .( chances of it happening so are extremely remote , because in this case the surplus drawn electrical energy , according to the law of conservation of energy , would be dissipated into heat )

Also taking efficiency into account , to give an output of 620 Watts , the input has to be somewhat more .

I am myself not sure , so please englighten me on the following -

If an smps is rated for 620 true watts as in corsair's case , would it actually be drawing from the mains that much amount for conversion into dc for the further supply or would it draw only a little more than what is required to handle the wattages of the components to which it is supplying.

Can Bullzi's problem be solved if instead of 600VA he goes for 1500 VA as that would translate to more than 620 watts ?

OR is it really as you have said the PFC thingy , screwing around ?

What all are the solutions for someone who already has purchased this smps ?

[BULLZI]

Hey thats some important points to be noted. Hope someone can answer/suggest on these queries.

I am going today for RMA. Dunno whether I will get an RMA or not.

[ancientrites]

AFAIK it happened to me twice when i owned zebronics 400watts and zeb 500 watts.But i still own 500watts as spare if my current zeb730watts blews up.

1) Is it possible that the psu suddenly got a short circuit connection inside it?
not everyone is lucky.yes its possibel

2) Am I going to get an RMA for this type of problem?
no doubt you should get it


dun worry bro be cool

[Big-G]

Bullzi , this is what I learnt on various sites.

PSU with an Active PFC on battery mode has the potential to draw it's rated power and infact it does draw it's rated power as it has an additional circuit ( electronic circuit of ICs , diodes , transsitors et al ) to do the Power Factor Correction .

So in your case your Corsair HX 620 , worked fine on mains AC by actually drawing it's rated power ( about which you never came to know , as there was no means for you to know how much power is the PSu drawing) .On battery mode the same thing happened and hence it overloaded your UPS , as your UPS ka pf is .6 and that translates to 1000*.6 = 600 Watts , ie below par which your UPS can handle ( your monitor too needs some power as do other connected peripherals )

Another factor which screwed up things was that the corsair HX 620 though rated at 620 Watts by the company , actually can give an out put of more than 700 Watts ( as per the reviews by silentpcreviews.com , hardwaresecrets.com et al )

Also incase you are not convinced with this explaination then please read APC knowledge base and you'll agree.

Computers containing PFC (Power Factor Corrected) power supplies and their use with Back-UPS or Smart-UPS SC UPS.

Question
This document will explain why some BackUPS or SmartUPS SC models may drop the load or trigger an Overload indication while on battery, when the attached load consists of PFC (power factor corrected) power supplies.

Answer

Power Factor Corrected (PFC) power supplies are becoming increasingly popular in desktop PC’s in North America. Contributing to this trend is the fact that Energy Star 4.0 compliance as of July 2007, requires the use of PFC in desktop PC’s.

Please see reference to the Energy Star 4.0 compliance Tier 1 at www.energystar.gov/

What is Power Factor and Power Factor Correction?
Power factor is the percentage of electricity that is being used to do useful work. It is expressed as a ratio. For example, a power factor of 0.72 would mean only 72% of your power was being used to do useful work. Perfect power factor (which in this case is being achieved by the computer’s PFC power supply) is 1.0 (unity), meaning 100% of the power is being used for useful work. Power Factor Correction is a circuit design technique to increase the power factor of a device so that it approaches 1, or unity power factor.

Although computer power supplies draw only a fraction of their full capacity during it’s steady state(normal operation), PFC power supplies have the potential to draw their full capability during initial inrush. "Inrush" or "Inrush Current" refers to the maximum instantaneous input current drawn by an electrical device when first turned on.

A computer’s power supply may also be subjected to a period of inrush, while the UPS is changing state (switching from utility power to battery power and back). Back-UPS and Smart-UPS SCs may experience up to an 8ms transfer time during this period. This is just long enough to remove power from the PFC power supply, resulting in a momentary inrush of the PFC. Once the UPS changes states from "Online" (passing utility power) to "Onbattery" (passing power from the UPS's internal battery), the momentary inrush from the attched equipment subjects the UPS to the PFC power supply’s maximum power draw, resulting in a potential Overload condition or dropped load.

An Energy Star 4.0 compliant power supply has to be more than 80% efficient. For example, if a PFC power supply is delivering 600W output power, its ‘input’ power can be as high as 750W. .

This ‘input’ power should be the basis for sizing the UPS, so as not to Overload the UPS. This can be calculated by taking the PFC power supply’s rated output power and multipling it by 1.25 as follows;

600W x 1.25 = 750w

Here is the link

http://jpaa-en.apc.com/cgi-bin/jpaa_...i=&p_topview=1

Lastly and the most , nobody in India needs an Active PFC PSu , as this is just a marketing gimmick as we in India are not billed on VA , moreover PSU without a pfc or a passive PFC never draw there rated power when on battery mode , they draw only that much power as is required .It's just that in some developed countries it has become a legislative norm to have an active PFC , in psu's that psu manufactureres are adding this additional pfc circuit in the psu .

Pseudo sine wave or true sine wave has got nothing to do with your screw up .

Anyway I wish to stand corrected as I was myself thinking of going for the same psu combo.

Power Factor Correction Decoded

PFC decoded
Originally published 2003 in Atomic: Maximum Power Computing


Last modified 01-Apr-2008.


Companies that make PC Power Supply Units (PSUs) find it difficult to make their products stand out from the crowd. On top of the increasingly outrageous wattage ratings (a quality 300 watt PSU is enough to run practically every PC out there, but lots of people buy something with a much higher rating just for the heck of it), there are multiple fans, funky cables, gold-plated connectors, little lights...

...and Power Factor Correction (PFC).

A PC PSU doesn't have to have PFC, but practically all of them do these days, because many countries have regulations that require some kind of PFC. Most PSUs have passive PFC; fancier models have active PFC.

Active PFC, your friendly shiny-suited PC salesman will explain, is more efficient. He may or may not also say that it'll save you money on your electricity bill.

Either way, he's full of crap.

Power factor correction (PFC) is, essentially, what you do to complex AC loads (such as PC switchmode power supplies) to make them act more like simple loads (such as toasters).

Alternating current oscillates continuously. 50 times a second, here in Australia and in most other 220/240 volt countries; 60 times a second, everywhere else (people living in East Elbonia and using 153 volt DC mains and four pin plugs need not e-mail me to complain about this generalisation).

If you plot voltage versus current drawn for a simple ("resistive") load in an AC circuit, the current will neatly follow the voltage, perfectly in sync. At the points in the AC cycle when there's the maximum voltage across the load, the maximum current will flow. And when the voltage reverses during each oscillation, so does the current. This is all very simple and sensible; it's what you'd expect AC to do, by applying the volts equals amps times ohms rule you learned for direct current circuits in high school physics. Or should have learned, anyway.

If you multiply the root-mean-square (RMS) voltage by the RMS current of a simple AC circuit like this, you get its power in watts. Again, this all works like DC electricity.

Complex AC loads are not this simple. Their current draw doesn't follow the voltage; it's out of sync. This is because the load is capacitive or inductive - "reactive". Reactive loads can even be both capacitive and inductive, in different mixtures over time.

If you think of a resistive load as just a length of hose, that needs a certain constant pressure to get a certain constant amount of water flow, then a reactive load is a contraption involving buckets and water balloons. Things are filling up and emptying at their own rates, in response to the water that's being pumped in.

The more complex a load is, the more out of sync the current can be with the voltage, and the worse the device's "power factor" will be. The current waveform doesn't even have to look like the voltage waveform; it can be all sorts of funny shapes. The worse the power factor, the more apparent AC power you'll need to run the device.

Multiplying a reactive load's RMS voltage and RMS current will give you the circuit's "volt-amps" (VA, which you may remember seeing on the spec sheets for uninterruptible power supplies) rating. This is its apparent power, but not its real power. Power equals VA times power factor, and power factor is the cosine of the phase angle between voltage and current.

(You're allowed to not spend time thinking about this bit. I won't be asking questions later. The phase angle thing can end up very difficult to calculate, anyway, when a load's current waveform is a funny shape, and not just a nice constant sine wave like the voltage waveform.)

A device that draws an apparent power of 1000VA and has a 0.5 power factor is consuming 500 watts of power. Not 1000. Put that device in a thermally insulated room and measure the temperature rise and it'll be the same as if you put a nice resistive 500 watt heater in there.

The VA rating is how much power the device seems to be consuming, if you don't look at the volts-versus-amps graph. But it's actually storing some power in its reactance during one portion of each AC oscillation, and returning it in the next. All of this current flow looks like real power consumption to someone who's just hooked up a couple of multimeters.

Actually, it's even more confusing than this, because the current waveform is unlikely to be sinusoidal, so it can't really be said to have a phase relationship with the voltage waveform, and frequency analysis and other evils are called for. Handwave, handwave; this stuff needn't detain us here.

Proper power meters, like the induction wheel meters that the electricity company uses to figure out how much money household power customers owe them, are meant to measure true power, not apparent power. They're supposed to compensate for differences in phase between voltage and current. How well they do that is a topic for animated discussion among people who seldom have anything better to do on a Saturday night, but the meters do more or less get it right.

So it doesn't matter much how bad the aggregate power factor of your various appliances is, at least as far as a domestic electricity bill goes.

Devices with low power factors, however, pollute the mains. Their odd current draw shifts the mains voltage around in similarly odd ways.

Consider a device with a power factor of zero. That'd be a perfect inductor - a thing that can only exist in physics-experiment-land - but it serves to illustrate what's going on here.

Feed AC through a perfect inductor and you'll be able to measure a current flow, perfectly out of phase with the mains supply (a "90 degree phase angle"). This means no actual power will be consumed; the inductor will draw current on one quarter of the cycle and deliver it back again on the next.

The AC supplier won't be happy with this, though, because it'll have to deliver current one half of the time, and handle that same current coming back again the other half of the time. This current doesn't indicate real power consumption, but it is real current. And the more of this real current the mains grid has to handle, the thicker the wires have to be, the bigger the distribution transformers have to be, the more power will be wasted thanks to cable resistance, and so on.

Lots and lots of reactive loads - an office full of PCs, say, or various other gear - can leave the mains waveform looking very weird indeed. This may be bad for other devices trying to run from mains power, and is annoying to the electricity company, for the abovementioned reasons.

Industrial power customers are, for these reasons, commonly billed according to their equipment's power factor, as well as its power consumption. The more of a mess they make of the mains, the more they pay.

Well, that's the theory, anyway; the formulae used to figure this stuff out can be baroquely complex. If you want mystifying equations, always look to accountancy before physics.

And so, Power Factor Correction (PFC) is used. PFC makes reactive loads look more like resistive ones, from the outside.

Passive PFC is just compensatory capacitance or inductance across inductive or capacitive loads; it tries to iron out the oddities with passive components.

Active PFC is an actual second circuit. It sucks power from the mains in a resistive way, and feeds it to the low power factor circuit on the other side, isolating the mains from whatever that circuit is doing. Active PFC can iron out lousy power factor better, but it's less efficient, not more; an active PFC circuit will waste some power (at least 10%, in this case) as heat, just like every other circuit in the world.

This can still work out as a good deal for industrial customers, because improving the power factor of componentry reduces the amount of power generation and distribution infrastructure needed to support it. Thinner wires, smaller transformers, smaller generators, et cetera.

But if you're not being billed by power factor - and if you're a home or small business, you're probably not - then an Active PFC PSU, or any other kind of power factor corrected hardware, isn't going to consume any less real power than cheaper gear without PFC. It'll actually probably consume a little bit more, and that little bit more will be noticed by your electricity meter, though the cost per year of this extra is unlikely to be more than you can find down the side of the couch.

If you want to do your part to clean up the mains, then PFC PSUs are a good idea. This might also qualify as enlightened self-interest, because the rate that domestic power consumers are charged per kilowatt-hour is no doubt influenced by their overall power factor. Everyone who swaps out low-power-factor gear for PFC gear lightens the load on the grid, and this may delay power price rises (or, if you live in Happy Land, actually cause the price per kilowatt-hour to drop).

Active PFC PSUs may also deal with lousy mains power better than passive PFC units, but PC PSUs generally handle spikes and surges and dropouts pretty well already, and a proper outboard power conditioner (as shown in this piece) is a better solution to that problem, anyway.

So by all means, buy an Active-PFC-equipped PSU if you like; they do no harm, and they're generally high quality in other respects as well. But don't think that PFC of any kind is going to save you any money, if you're using ordinary domestic power.

The difference between car salesmen and computer salesman is that car salesmen know when they're lying, so someone who tells you Active PFC makes a PSU more efficient is not necessarily trying to pull the wool over your eyes. You'd still probably do well to buy from someone else, though.


Link
http://www.dansdata.com/gz028.htm

Anybody here , who opines differently for Bullzi's screw up ?

Any more reasons with proof for the same like not true sine wave , hence the screw up .

Do you agree Aditya .Please correct me if I am wrong.

Bullzi please keep us posted about the status of your Corsair .

Did you get the RMA

Did you again tried using the same combo ? If yes what was the result on battery mode ?

I am curious to know and educate myself though at your cost

[dOm1naTOr]

Hi, u can check if ut PSU still turns on w/o connecting it to mobo.
First detack all connectors from mobo, drives etc.
Then take a small insulated copper wire and strip off the insulation on both ends.
Now insert either ends into the green and black(any) of the 20+4 pin mobo power connector.
This shud turn on the PSU and the fans shud be spinning, and lastly-there shudnt be ny sparks inside the PSU

If it works fine, then the problem is with the power output of PSU nd u can get the warranty.
U can also try using a stabilizer in b/w the UPS and the PSU to smoothy out the rising edge of the pseudo sine wave nd modify it to more pure sinewave like. And remember to use gud stabilizers like V-Guard ones that we use with refridgerators or ACs.

[sagargv]

@big-G , the surge current idea which u think is responsible is acceptable .. but a few questions :

1. if the psu in bullzi's pc took 700W power , then the load on the ups is about 1100 kVA which i doubt is something beyond a apc 1000 kVA to handle for a few milliseconds.

2. If the psu didnt get enough power , could you explain why it blew up instead of shutting off .

3. Could you explain why this of "inrush" of current just after the ups switches occur only in PFC capable psu's ? why not in other psu's too ? Why is it more pronounced in PFC capable psu's ?

I agree , ur explanation seems quite logical but i can accept it only if i understand the answers to the above questions.

[adithyagenius]

@everyone
sry lots of exams and i come home once a week.
anyway, what big-g said is right. Only industrial customers are charged for reactive power. Industries use lots of induction motors and hence power factor drops. To reduce their electiricity bills, they use shunt capacitors as pfc. Energy Star 4.0 included pfc to improve the domestic consumption and it is not mandatory in india. Unfortunately we cannot buy a psu which meets the requirements of 9800gx2, 3870x2 or 9600gt sli without active pfc. The first 2 require a 8pin and a 6 pin pci-e connector. 620hx, 550vx from corsiar are the cheapest that meet the requirements. Anything higher than 620hx's rating is pretty much useless unless going for quad sli.
I had 1 hour chat with some apc tech support guy. He convinced me that APC uses stepped sine wave approximation and there is no need to worry about active pfc. The problem bullzi is facing is not widespread. I have already talked to people who are using apc backup series with active pfc psus. Cheapest UPS with true sinwave from APC costs 10k. The price is due to high voltage regulation which is useless because psu already does a great job. 620hx takes care of all power problems except power cuts.
ATI Hyderabad recently bought around 180 620HX. I will found out what UPS they are using. Will return after 25 days.

[Big-G]

Before I even attempt to answer your questions sagargv or analyze what could have possibly happened , I need to know in black and white the following facts from Bullzi -

What is the status of Your UPS? Is it working Ok with a different PSU ( any brand) .This I need to know so as to rule out a concern - Could this screw up be due to some faulty UPS?

I have had in the blast fumed my APC UPS twice ,some moisture creeped inside it , actually a lot of moisture due to the AC being on whole night , a thick film of moisture had condensed on the floor and the moment I switched on the UPS it fired up.

Are all the sockets of the UPS ( battery ones and the mains one) working fine on a different PSU.

If you havent checked out and ruled out a faulty UPS then please do so before attempting anything else and keep us posted.

Are you sure that your PSU has blown up and is absolutely dead.Have you even tried confirming it?May be it's the UPS which has gone and you are not aware of it as you havent checked it out.Check your UPS first elsewhere.


I again emphatically say that a simulated sine wave has absolutely no role to play whatsoever in blowing up a Power Supply .It's just the under powered UPS which is responsible for it.Upgrade your UPS for this PSU and voila you'll have no problem.

And above all why the hell do you need an Active PFC power Supply in India .

Got money to burn - eh - come to me - I 'll help you how .

dominator


U can also try using a stabilizer in b/w the UPS and the PSU to smoothy out the rising edge of the pseudo sine wave nd modify it to more pure sinewave like. And remember to use gud stabilizers like V-Guard ones that we use with refridgerators or ACs.




AVR ( automatic Voltage Regulation ) doesn't matter since it's not modifying the sine wave, it's merely drawing more or less current on the mains side as voltages rise or fall.

AVR would play an absolutely ZERO role in smoothing out the rising edges and on the contrary providing an AVR between the PSU and the UPS would be highly irritating .It would continuosly producing a cutting sound.yeah you can place the AVR before the UPS for double protection and not after the UPS .AVR is meant to be used with a true sine wave and not with a stepped sine wave or whatever modified sine wave

Aditya

Not trying to under estimate your understanding of the topic under discussion but just for the sake of adding to my knowledge and / or correcting myself , I need to know that where exactly did you read that ACTIVE PFC is meant to work with true sine wave only and not with simulated or stepped sine wave .Can you please provide a link or something to confirm what you claim.

There are PSU's with active pfc which are compatible both with pseudo as well as real sine wave ups and this fact is mentioned on them very explicitly .Ex. power supplies from enermax and various others.

He convinced me that APC uses stepped sine wave approximation and there is no need to worry about active pfc. The problem bullzi is facing is not widespread. I have already talked to people who are using apc backup series with active pfc psus.

Exactly , and I strongly feel that it's bullji's UPS at fault , and may be as per APC's knowledge base , his UPS is underrated for this PSU





Cheapest UPS with true sinwave from APC costs 10k. The price is due to high voltage regulation which is useless because psu already does a great job.620hx takes care of all power problems except power cuts.



I completely agree






ATI Hyderabad recently bought around 180 620HX. I will found out what UPS they are using. Will return after 25 days

I am waiting very anxiously to know the same

Sagargv , we are discussing in VA , not in KVA .

KVA is a thousand times more than a VA and one would never ever in life need a 1000KVA , 1100KVA UPS or PSU

[Big-G]

ATI Hyderabad recently bought around 180 620HX. I will found out what UPS they are using. Will return after 25 days.

25 Days are over dude .

So which UPS are those guys using and of what brand and ratings? Also how are the faring ?

[entrana]

dont know about all you guys opinions , but my friend has the same psu and is using it finely with a microtek ups 800va. works fine and works good, the ups costs around 4k and has a good battery life upto 30 mins, what more do u need??

[realdan]

i m using one of my corsair HX620Ws on one of my PC using APC Backup-UPS AVR Pro 500VA..no problem as of now...

and before on another PC i was using the APC 650VA one with no issue but later changed to APC 800VA as i wanted to use the 650VA one for routers

I have faced similar problem with an antec sp400W one..a loud POP! when i switch on the UPS or power...got it replaced under warranty...

[Plasma_Snake]

I'm having almost the same trouble. As soon as the power goes off, my UPS starts squealing like a pig as if it has completely drained its power and shuts down within 5 seconds or so. It is not able to handle my PSU. My UPS is a Microtek 1KVA model and PSU is Corsair TX750W. So as a result I need u guys to tell me a good PURE SINE WAVE UPS, preferably before Wednesday in the range of 5-7K, that can handle my system and give backup of atleast 10 mins. Config is below:

1. Intel C2D E8400 (stock clock @ stock HSF)
2. ASUS P5QC
3. Patriot 2x2GB DDR2 800MHz RAM
4. MSI HD4850
5. WD 640GB AACS + Seagate 400GB + Seagate 160GB

Besides the system my Creative T6060 speakers and my LCD TV, which I use as display, is also connected to the UPS. Please help me guys as power cuts are frequent here and last night when power came back and I rebooted, Check Disk ran automatically to correct the system partition as it had developed few bad areas due to this sudden shutdown. I'm very afraid about my drives's security, please help me out brothers!

[entrana]

dude ur psu is an overkill. its draining unnecessary power it doenst need to.

[Plasma_Snake]

Dood, I know and I have it 'cause I don't intend to use this config for more than 6 months so have taken a big headroom in the power department as my next rig would be Crossfire or Sli machine or maybe even a Quad so will retain the PSU for that and moreover, the Corsair advertises that under idle conditions PSU power usage is 130W, 325W under typical load and 650-750W under full load so I dont' think that with my current config, load would even exceed 450W. I just need a Pure Sine wave UPS for this PSU as my current one just dies as soon as the power goes off. AFA electricity bill is concerned, all I can say is that we've got "JUGAAD" at both our and Electricity Dept. end I'm just biding my time till I get my laptop in a month or two and then it would be my download rig as I also acknowledge the fact that machine of such heavy proportions is not suitable to be used as a download rig, its an insult to the rig itself