Power Surge
Greetings
I'm currently restoring a system that was hit with a power surge where the following were fried: PSU Motherboard Hard Drive CDROM CDRW Network (PCI) Audio (PCI) However the following components from the same system survived: CPU RAM (all 3 sticks that were installed) AGP video Modem (PCI) Floppy Speakers Monitor Keyboard/Mouse I just find it curious that components I thought were sensitive to voltage like the CPU and RAM would survive while other components wouldn't. The core on the audio card actually popped (I found the center of the silicon at the bottom of the case). I keep telling people to get a UPS or a good surge protector but no one listens until they have to pay $$$ Anyone else have a horror story to tell? Dave. |
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"Ben" wrote in message
lid wrote: As for surge protectors, they can do SOME good, but the UPS is the way to go. Particularly if the UPS does a conversion from A/C to D/C and back to A/C during normal operation. Many of the cheap ones simply pass through the normal A/C with a relay and then do a restoration via the battery when it fails. If I get one of these UPS surge protectors would that mean I could use my computer during a thunder storm? thanks, Ben Better to install a whole-home surge protector rather than the cheapie surge protectors you buy at the store. They cost about the same (unless you need to have an electrician do the wiring for the home surge arrestor). Then everything in your house is protected. however, surge arrestors only protect against surges. They don't protect against sags. Your power supply would have to suck more current to offset the loss in voltage until the sag became too low (your lights and television will work but not the switching power supply in your PC). Surge protectors also do little to condition the line (but then some cheapie UPSes are just pass-through units, too). I prefer to get a UPS that generates the power output rather than just pass it through. A UPS with an isolating transformer is even better but then they get really heavy; mine weighs 60 pounds for the case with transformer and another 60 pounds for the 2 batteries, for a total of 120 pounds (and has true sinusoidal output and too many other goodies to list, but then it cost as much as a high end PC). But even a cheapie UPS is usually better than a surge protector. You could spend $60 on a good point-of-use surge protector (i.e., you plug it in the wall install of the point-of-entry whole-home surge arrestor) and hope that it is still working (since many never tell you when they've gotten fried) or you spend twice that much on a low-end UPS that protects better. When the power goes out, the surge protector doesn't do anything. It can be handy to continue computing while the power is out. You're television don't work so sit at your PC. You can check the weather, especially if that caused the outage. You can contact your power company (since calling in puts in the queue with everyone else trying to report the outage). You can even hook up a low-power intensity lamp so you can see without having to drain the batteries in your flashlights. I actually have a small UPS left over from a prior system used to power the cable modem and a flourscent lamp, and it's small enough to tote around the house to use elsewhere. Sure beats sitting in a dark house. -- __________________________________________________ __________ ** Share with others. Post replies in the newsgroup. ** If present, remove all "-nix" from my email address. __________________________________________________ __________ |
What is this sag that causes problems? Computer power
supplies are some of the most robust electronics in the house. AC electric can drop to 90 VAC (for 120 VAC) or 190 VAC (for 230). The computer must operate interrupted. Even with a full load of peripherals, the computer must power up just fine when AC mains voltage has sagged that low. Incandescent bulbs would be at less than 40% intensity and the computer must work just fine. However many buy power supplies only on on specification - price - and get what they paid for. Sags must not damage any computer. However if you are still using disk filesystems such as FAT, then you still data destruction from excessive brownouts or blackouts can occur. Again, the UPS is nice, but not necessary for hardware protection if computer hardware is properly selected and installed. I never use plug-in UPSes or any other grossly overhyped and ineffective plug-in protectors. I go online during every thunderstorm. Never shutdown for such storms. Never unplug anything. Suffered some direct strikes and never suffered damage. No damage because the technique is same well proven methods demonstrated in 1930s research papers. Those plug-in protectors fundamentally violate those principles. Summary is provided in "Opinions on Surge Protectors?" on 7 Jul 2003 in the newsgroup alt.certification.a-plus or http://tinyurl.com/l3m9 BTW, plug-in surge protector and plug-in UPS use equivalent circuits to provide the same ineffective protection. There is no such thing as blocking or stopping a surge even with a transformer. Transformer can help to divert the surge. But again, it still requires the well proven 'whole house' protection 'system'. Yes - a 'system' that includes the most critical 'system' component - earth ground. Plug-in UPS serves one primary function - data protection. Surge protector is defined by its most critical component - that plug-in protectors just don't have and forget to mention. Read that above, previous summary discussion for details. Vanguard wrote: "Ben" wrote in message If I get one of these UPS surge protectors would that mean I could use my computer during a thunder storm? thanks, Ben Better to install a whole-home surge protector rather than the cheapie surge protectors you buy at the store. They cost about the same (unless you need to have an electrician do the wiring for the home surge arrestor). Then everything in your house is protected. however, surge arrestors only protect against surges. They don't protect against sags. Your power supply would have to suck more current to offset the loss in voltage until the sag became too low (your lights and television will work but not the switching power supply in your PC). Surge protectors also do little to condition the line (but then some cheapie UPSes are just pass-through units, too). I prefer to get a UPS that generates the power output rather than just pass it through. A UPS with an isolating transformer is even better but then they get really heavy; mine weighs 60 pounds for the case with transformer and another 60 pounds for the 2 batteries, for too many other goodies to list, but then it cost as much as a high end PC). But even a cheapie UPS is usually better than a surge protector. You could spend $60 on a good point-of-use surge protector (i.e., you plug it in the wall install of the point-of-entry whole-home surge arrestor) and hope that it is still working (since many never tell you when they've gotten fried) or you spend twice that much on a low-end UPS that protects better. When the power goes out, the surge protector doesn't do anything. It can be handy to continue computing while the power is out. You're television don't work so sit at your PC. You can check the weather, especially if that caused the outage. You can contact your power company (since calling in puts in the queue with everyone else trying to report the outage). You can even hook up a low-power intensity lamp so you can see without having to drain the batteries in your flashlights. I actually have a small UPS left over from a prior system used to power the cable modem and a flourscent lamp, and it's small enough to tote around the house to use elsewhere. Sure beats sitting in a dark house. |
"w_tom" wrote in message
What is this sag that causes problems? Computer power supplies are some of the most robust electronics in the house. AC electric can drop to 90 VAC (for 120 VAC) or 190 VAC (for 230). The computer must operate interrupted. Even with a full load of peripherals, the computer must power up just fine when AC mains voltage has sagged that low. Incandescent bulbs would be at less than 40% intensity and the computer must work just fine. However many buy power supplies only on on specification - price - and get what they paid for. Sags must not damage any computer. However if you are still using disk filesystems such as FAT, then you still data destruction from excessive brownouts or blackouts can occur. Again, the UPS is nice, but not necessary for hardware protection if computer hardware is properly selected and installed. I never use plug-in UPSes or any other grossly overhyped and ineffective plug-in protectors. I go online during every thunderstorm. Never shutdown for such storms. Never unplug anything. Suffered some direct strikes and never suffered damage. No damage because the technique is same well proven methods demonstrated in 1930s research papers. Those plug-in protectors fundamentally violate those principles. Summary is provided in "Opinions on Surge Protectors?" on 7 Jul 2003 in the newsgroup alt.certification.a-plus or http://tinyurl.com/l3m9 BTW, plug-in surge protector and plug-in UPS use equivalent circuits to provide the same ineffective protection. There is no such thing as blocking or stopping a surge even with a transformer. Transformer can help to divert the surge. But again, it still requires the well proven 'whole house' protection 'system'. Yes - a 'system' that includes the most critical 'system' component - earth ground. Plug-in UPS serves one primary function - data protection. Surge protector is defined by its most critical component - that plug-in protectors just don't have and forget to mention. Read that above, previous summary discussion for details. Vanguard wrote: "Ben" wrote in message If I get one of these UPS surge protectors would that mean I could use my computer during a thunder storm? thanks, Ben Better to install a whole-home surge protector rather than the cheapie surge protectors you buy at the store. They cost about the same (unless you need to have an electrician do the wiring for the home surge arrestor). Then everything in your house is protected. however, surge arrestors only protect against surges. They don't protect against sags. Your power supply would have to suck more current to offset the loss in voltage until the sag became too low (your lights and television will work but not the switching power supply in your PC). Surge protectors also do little to condition the line (but then some cheapie UPSes are just pass-through units, too). I prefer to get a UPS that generates the power output rather than just pass it through. A UPS with an isolating transformer is even better but then they get really heavy; mine weighs 60 pounds for the case with transformer and another 60 pounds for the 2 batteries, for too many other goodies to list, but then it cost as much as a high end PC). But even a cheapie UPS is usually better than a surge protector. You could spend $60 on a good point-of-use surge protector (i.e., you plug it in the wall install of the point-of-entry whole-home surge arrestor) and hope that it is still working (since many never tell you when they've gotten fried) or you spend twice that much on a low-end UPS that protects better. When the power goes out, the surge protector doesn't do anything. It can be handy to continue computing while the power is out. You're television don't work so sit at your PC. You can check the weather, especially if that caused the outage. You can contact your power company (since calling in puts in the queue with everyone else trying to report the outage). You can even hook up a low-power intensity lamp so you can see without having to drain the batteries in your flashlights. I actually have a small UPS left over from a prior system used to power the cable modem and a flourscent lamp, and it's small enough to tote around the house to use elsewhere. Sure beats sitting in a dark house. If the voltage drops on the input side but you still have the same power demands on the output side and where you must maintain the same voltage requirements with the same demand for current, how does the power supply make up for the deficiency in input voltage? -- __________________________________________________ __________ ** Share with others. Post replies in the newsgroup. ** If present, remove all "-nix" from my email address. __________________________________________________ __________ |
On Sat, 30 Aug 2003 01:59:03 GMT, "Vanguard"
wrote: If the voltage drops on the input side but you still have the same power demands on the output side and where you must maintain the same voltage requirements with the same demand for current, how does the power supply make up for the deficiency in input voltage? Switching opwer supplies monitor output voltage. They typically maintain the same switching frequency but as output drops, there will be increase in the duration of the "on" cycle to keep the voltage up. So, whether the input changes or the load changes, or both, the appropriate duration of on-cycle will change, up until the limits of the heat dissipation (longer on cycle generates more heat) or voltage drop below minimal allowed, generally due to inadequate sized transformer per load applied. Dave |
Others have summarized your answer. Some numbers. A
switching power supply first ups the 120 VAC to about 300 volts DC (and yes, those 300 volts did hurt). Then it oscillates that 300 DC voltage through a transformer, rectifies it, and creates the +5, +3.3, + 12 etc. Notice the so many transitions. 120 VAC to 300 VDC to various low voltage AC to regulated 3.3, 5, and 12 DC. With all those transitions, it becomes easy to take a widely varying, AC input voltage to create a noise free, galvanically isolated, robust, and well regulated DC voltage. Vanguard wrote: If the voltage drops on the input side but you still have the same power demands on the output side and where you must maintain the same voltage requirements with the same demand for current, how does the power supply make up for the deficiency in input voltage? |
"Vanguard" wrote in message .net... "David LeBrun" wrote in message e.rogers.com Greetings I'm currently restoring a system that was hit with a power surge where the following were fried: PSU Motherboard Hard Drive CDROM CDRW Network (PCI) Audio (PCI) However the following components from the same system survived: CPU RAM (all 3 sticks that were installed) AGP video Modem (PCI) Floppy Speakers Monitor Keyboard/Mouse I just find it curious that components I thought were sensitive to voltage like the CPU and RAM would survive while other components wouldn't. The core on the audio card actually popped (I found the center of the silicon at the bottom of the case). I keep telling people to get a UPS or a good surge protector but no one listens until they have to pay $$$ Anyone else have a horror story to tell? Dave. Sounds like you (or your customers) need to check into using better power supplies. When not protected by a UPS, mine have simply popped the breaker on the backside or blown a fuse (which sometimes requires me to open the PSU to replace it) or just tripped on the overvoltage and you wait until it resets and the line voltage is okay to power back on. By the way, it isn't just surge protectors and, better yet, UPSes for which customers never listen. They don't listen regarding backups, either. When they whine about really needing to get their data back, they look like deer in headlights when you ask about their backups. -- __________________________________________________ __________ ** Share with others. Post replies in the newsgroup. ** If present, remove all "-nix" from my email address. __________________________________________________ __________ I'm not sure how it was connected when the surge happened. I know it now has an Enermax PSU which I've never had a problem with. I also know that 2 or 3 other people have worked on the system before it came to me so no telling how or what caused the problem and what was done to try to fix it. I opened the case and found remnants of drink spills, a cpu heatsink with about 5 pounds of dust under a fan whose bearings are on the way out, wiring nest sitting right in front of the cpu heatsink, no case fan and the psu vent blocked with another wiring nest. Anyone that actually knows what they're doing should have fixed at least one of these problems by force of habit as far as I'm concerned. First thing (rather second...first I just stood there shaking my head) was to start cutting a hole in the case for a fan! I event went as far as lapping the heatsink because I knew heat was going to be a real problem. Don't know who did the work on it when it came to me but I know I wouldn't have them work on a system belonging to my worst enemy! What really bothers me is there are some people who charge an arm and leg to build/repair systems and what you get is something that looks like it came out of a meat grinder. I had installed backup software originally and with the burner installed there shouldn't have been any problem with the hard drive failing but like you said...they just never listen. Dave. (sorry for the rant) |
The plug-in UPS serves one primary function. It protects
data from power problems. It does not protect hardware. Did you read the long list of exemptions attached to that warranty? Good luck if you need to have that warranty honored. I have a UPS right here for 120 volt operation. To generate (in battery backup mode) what is considered 120 volts, it outputs two square waves of 200 volts with a 270 volt transient between those square waves. This output could be destructive to some appliances such as small electric motors. However computers are so resilient that even this harsh UPS output will not harm computers. The plug-in UPS is for data protection. Computers already (should) have internal protection which is why many UPSes do not damage a computer. David LeBrun wrote: OK...this is getting a little too technical for me (I am by no means an electrician) but I guess I understand the basic principles. I do however find all these details interresting even though some of it is way over my head. I do have to agree that there are cheap UPS units and then there's REALLY CHEAP units. I think that any "consumer" or "retail" UPS is going to at least be cheap relative to any "industrial strength" unit which probably means that the units I have are at least cheap. I have one which (now that I really look at it) looks like nothing more than a power bar with a battery in it. The other one is a big and heavy metal box which has more guts in it judging by the soft hum that comes from it during normal operation and not so soft hum when disconnected from AC. All I know is if anything were to happen to my equipment by these things not doing what was advertised I would just have to cash in on the warranties offered by the manufacturers and if this casualty system were mine hooked up to one of my UPS units you can be sure they'd be footing the bill to get the parts replaced. Dave. |
"kony" wrote in message
On Sat, 30 Aug 2003 01:59:03 GMT, "Vanguard" wrote: If the voltage drops on the input side but you still have the same power demands on the output side and where you must maintain the same voltage requirements with the same demand for current, how does the power supply make up for the deficiency in input voltage? Switching opwer supplies monitor output voltage. They typically maintain the same switching frequency but as output drops, there will be increase in the duration of the "on" cycle to keep the voltage up. So, whether the input changes or the load changes, or both, the appropriate duration of on-cycle will change, up until the limits of the heat dissipation (longer on cycle generates more heat) or voltage drop below minimal allowed, generally due to inadequate sized transformer per load applied. Dave And that means more current is drawn on the input side, right? -- __________________________________________________ __________ ** Share with others. Post replies in the newsgroup. ** If present, remove all "-nix" from my email address. __________________________________________________ __________ |
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